Nitrogen  Partition  in  Repeated 

Fasting 


, 

By  PAUL  LDWARD  HOWL 

B.5.  University  of  Illinois,  1906 
M.A.  University  of  Illinois,  1907 


THL5I5 

c''C'r 


SUBMITTED  IN  PARTIAL  FULFILMENT  OF  THE  REQUIREMENT  FOR  THE  DEGREE 
OF  DOCTOR  OF  PHILOSOPHY  IN  PHYSIOLOGICAL  CHEMISTRY  IN  THE 
GRADUATE  SCHOOL  OF  THE  UNIVERSITY  OF  ILLINOIS 


Easton,  Pa.  : 

Eschenbach  Printing  Company 

. 1911 


Nitrogen  Partition  in  Repeated 

Fasting 


By  PAUL  LDWARD  HOWL 

B.5.  University  of  Illinois,  1906 
M.A.  University  of  Illinois,  1907 


THL5IS 


SUBMITTED  IN  PARTIAL  FULFILMENT  OF  THE  REQUIREMENT  FOR  THE  DEGREE 
OF  DOCTOR  OF  PHILOSOPHY  IN  PHYSIOLOGICAL  CHEMISTRY  IN  THE 
GRADUATE  SCHOOL  OF  THE  UNIVERSITY  OF  ILLINOIS 


19IO 


Easton,  Pa.  : 

Eschenbach  Printing  Company 
1911 


Digitized  by  the  Internet  Archive 
in  2017  with  funding  from 

University  of  Illinois  Urbana-Champaign  Alternates 


https://archive.org/details/nitrogenpartitio00howe_0 


o 

a \ 


TP 


£W„ 


NITROGEN  PARTITION  IN  REPEATED  FASTING.1 

By  Paul  E.  Howe. 

Historical. 

The  literature  upon  fasting  is  large  and  may  be  divided  into  two  classes, 
that  presenting  data  upon  (a)  simple  fasts  of  (i)  short  duration,  and 
dealing  with  changes  in  body  weight,  nitrogen  partition,  the  blood,  tem- 
perature, secretions,  and  the  effect  of  drugs,  or  only  as  a preparation  for 
the  study  of  normal  or  pathological  metabolism;  (2)  more  or  less  pro- 
found fasts,  which  include  in  addition  to  those  changes  mentioned  above, 
losses  in  the  weight  and  differences  in  composition  of  the  organs  as  com- 
pared to  the  normal  organs;  and  (6)  repeated  fasts  in  which  (1)  the  ob- 
ject was  to  study  the  effect  of  repeated  fasting;  or  (2)  fasts  in  which 
the  main  object  was  not  the  study  of  repeated  fasting,  but  in  which  the 
subject  was  used  repeatedly  in  various  investigations,  no  regard  being 
given  to  the  original  conditions,  such  as  body  weight,  nitrogen  equilibrium, 
etc. 

Experiments  on  Repeated  Fasting. — Investigations  upon  fasting  have 
been  limited  mainly  to  the  lower  animals,  while  those  upon  repeated 
fasting  are  confined  entirely  to  them  unless  the  fasts  of  Sued1  are  to  be 
considered  as  repeated  fasts,  which  is  hardly  proper,  since  each  fast  was 
conducted  under  different  circumstances  as  regards  original  condition, 
body  weight,  time  of  year,  climate,  etc. 

Repeated  fasts  have  been  conducted  upon  dogs  by  Albitsky.3  His 
investigations  were  made  upon  four  dogs,  two  fasting  absolutely,  i.  e.t 
without  water,  to  a loss  in  body  weight  of  40.4  per  cent,  and  37.6  per  cent., 
in  twenty-nine  days,  and  fifteen  days  respectively,  and  the  second  time 
with  water  ad  libitum , with  a loss  of  53.2  per  cent,  and  45.8  per  cent, 
in  fifty-one  and  thirty  days,  respectively.  The  other  two  dogs  fasted  first 
1 Reprinted  from  the  Journal  of  the  American  Chemical  Society , 33,  215,  1911. 


4 


FASTING  STUDIES. 


with  water,  to  losses  of  41.5  per  cent,  and  38.7  per  cent,  in  thirty-four  days 
and  twenty-five  days,  respectively,  and  the  second  fast  to  a loss  of  43.7 
per  cent,  and  49.0  per  cent,  body  weight,  in  thirty-two  days,  and  thirty- 
eight  days  respectively.  Positive  conclusions  cannot  be  drawn  from 
Albitsky’s  results.  No  study  was  made  of  the  effect  of  a properly  con- 
trolled repeated  fast,  either  complete  or  with  water.  Hence  he  had  no 
basis  upon  which  to  compare  the  effect  of  water  upon  the  length  of  a 
fast.  A study  of  the  results  show  in  general  that  water  seems  to  lessen 
the  breakdown  of  the  body  tissues,  for  in  three  out  of  the  four  cases  the 
dogs  fasted  a greater  length  of  time  for  the  same  loss  in  body  weight 
when  they  received  water  than  when  no  water  was  given. 

Tuvim4  subjected  two  dogs  to  three  repeated  fasts  of  three  days  each, 
the  first  fast  being  absolute,  and  the  two  following  with  a large  water 
ingestion.  A third  dog  was  fasted  but  twice,  the  first  fast  being  abso- 
lute and  the  second  with  water.  His  experiments  were  to  study  the  effect 
of  water  upon  fasting,  and  only  the  respiration  data  were  observed.  His 
results  did  not  show  that  water  had  any  pronounced  effect  upon  the 
gas  interchange,  and  no  data  are  presented  which  would  show  the  effect 
of  repeated  fasting  upon  the  nitrogen  partition. 

Schulz  working  with  Mangold,9  Stiibel10  and  Hempel11  reports  results 
upon  repeated  fastings  in  dogs.  One  dog  weighing  16.1  kilograms  was 
fasted  for  thirty-two  days,  when  the-  premortal  rise  seemed  to  have  set 
in,  and  then  the  animal  was  fed  an  insufficient  nitrogenous  diet  for  nine 
days,  during  which  time  it  stored  23  grams  of  nitrogen.  This  nitrogenous 
feeding  was  followed  by  a seven-day  carbohydrate  feeding  period  with 
a loss  of  12.93  grams  of  nitrogen,  leaving  a storage  of  10.07  grams  of 
nitrogen  for  the  sixteen  days,  during  which  the  animal  was  fed.  This 
feeding  period  was  followed  by  another  fast  of  fourteen  days  with  a 
further  loss  of  27.61  grams  of  nitrogen  over  that  gained  and  lost  during 
the  feeding. 

This  same  dog  was  subjected  to  a similar  experiment  one  month  later. 
At  the  beginning  of  this  experiment  the  animal  weighed  19.6  kilograms 
and  probably  had  greater  fat  stores  than  in  the  first  experiment.  The 
dog  was  fasted  for  twenty-seven  days,  at  the  end  of  which  time  he  was 
so  reduced  in  strength  that  they  feared  he  would  die.  Schulz  described 
the  condition  as  a collapse.  Food  was  given,  400  cc.  of  milk  on  the  first 
day  and  300  grams  of  meat  per  day  for  four  days,  restoring  the  dog  to  a 
satisfactory  condition,  after  which  the  dog  was  fasted  further  for  sixty- 
one  days,  at  the  end  of  which  time  the  animal  was  very  weak,  although 
no  premortal  rise  had  occurred.  During  this  second  series  of  fasts 
the  dog  had  lost  208.4  grams  of  nitrogen  without  regard  to  the  nitro- 
gen balance  of  the  feeding  period,  while  in  the  first  series  of  fasts  the 
dog  lost  183.2  grams  of  nitrogen.  The  daily  average  nitrogen  excretion 


FASTING  STUDIES. 


5 


during  the  second  part  of  the  first  series  and  the  first  part  of  the  second 
series  was  less  than  that  in  the  first  fast,  while  the  average  nitrogen  ex- 
cretion in  the  final  fast  of  sixty-one  days  was  even  lower  than  the  nitro- 
gen excretion  of  the  feeding  period  when  sugar  was  ingested. 

Stiibel,10  working  on  another  dog,  obtained  a similar  lowered  nitrogen 
excretion  after  a short  feeding  period  in  which  the  dog  received  an  in- 
sufficient food  supply. 

Manassein5  reports  experiments  upon  the  repeated  fasts  of  three  rab- 
bits in  absolute  fasting,  and  Albitsky3  upon  nine  rabbits  fasting  either 
absolutely  or  alternately  with  water.  In  Albitsky ’s  experiments  the 
object  was  the  study  of  the  effect  of  water  upon  fasting  and  the  following 
conditions  were  in  force  in  his  work.  The  first  three  rabbits  were  fasted 
absolutely  while  the  remaining  six  rabbits  were  fasted  alternately  with 
and  without  water.  The  fasts  were  continued  to  a loss  of  40  per  cent, 
of  the  body  weight  and  it  was  found  that  with  each  succeeding  fast  there 
was  a tendency  toward  a decrease  in  the  daily  loss  in  body  weight.  Al- 
bitsky also  observed  that  the  recovery  was  slower  with  each  succeeding 
fast  and  that  as  a result  of  fasting  the  animals’  “oxidative”  properties 
were  increased  so  that  from  one  to  one  and  one-half  times  as  much  food 
and  twice  as  much  water  were  needed  to  keep  the  animal  in  a state  of 
constant  body  weight.  Pashutin2  concludes  from  the  work  of  these 
men  that  with  the  ingestion  of  water  there  is  a slower  loss  in  body  weight 
than  would  occur  in  absolute  fasting.  The  conditions  of  experimentation 
were  not  controlled  accurately  in  these  experiments  and  only  general 
deductions  may  be  drawn  from  the  results. 

Kagan6  conducted  experiments  in  repeated  absolute  fasting  upon  pigeons 
and  showed  in  the  birds  results  similar  to  those  obtained  upon  dogs  and 
rabbits,  i.  e.,  a slower  loss  in  body  weight  upon  repeated  fasting.  This 
decrease  in  the  loss  of  body  weight  does  not  continue  with  each  succeeding 
fast  but  remains  fairly  constant.  Albitsky3  reports  results  upon  pigeons 
which  confirm  his  findings  upon  rabbits.  He  also  gives  data  showing 
the  influence  of  water  upon  fasting. 

Ugrumoff7  in  two  experiments  upon  pups  showed  that  water  exerted 
a sparing  influence  upon  the  organs  over  the  loss  found  by  fasting  when 
a salt  solution  was  given.  Sadoven8  working  along  the  same  lines  sub- 
jected rabbits  to  repeated  fasts  under  varying  conditions  such  as  abso- 
lute, with  water,  or  with  salt  solution.  He  showed  that  salt  solution 
exerted  a sparing  influence  upon  the  loss  of  body  weight  as  compared 
with  complete  fasting,  while  water  exerted  a still  greater  influence. 

Bischoff  and  Voit13  made  a number  of  fasts,  twenty-eight,  upon  one 
dog,  under  widely  varying  conditions,  no  single  fast  being  more  than 
eight  days  long  and  some  were  for  only  one  to  two  days. 

Seeland14  conducted  experiments  on  short  repeated  fasts  with  pigeons 


6 


FASTING  STUDIES. 


and  roosters  and  showed  that  those  birds  which  were  subjected  to  re- 
peated fasts  of  one  to  three  days’  duration  gained  weight  more  rapidly, 
their  tissues  were  more  solid,  and  the  birds  hardier  and  stronger  than 
the  control  birds  which  were  fed  every  day. 

Richet15  fed  and  fasted  rabbits  alternately  in  periods  of  six  days; 
under  such  treatment  they  died  in  about  a month  and  a half.  Dogs 
subjected  to  a similar  treatment  lived  about  six  months. 

The  work  upon  repeated  fasting  which  has  been  cited  cannot  be  in- 
terpreted in  any  way  to  show  the  effect  of  repeated  fasting  with  water. 
The  only  cases  in  which  the  animals  were  fasted  repeatedly  and  absolutely 
were  those  of  Albitsky’s  rabbits  which  were  fasted  to  a loss  of  40  per  cent, 
of  the  body  weight.  The  most  of  the  data  presented  deal  largely  with 
the  changes  in  body  weight.  In  some  cases  the  respiration  data,  urine 
volume,  P205  and  urea  excretion  were  determined  but  no  accurate  data 
are  presented  upon  nitrogen  partition. 

Short,  repeated  fasts  upon  men  are  reported  by  Bucker,18  Smith,17 
Ranke,18  Pettenkofer  and  Voit,19  Oppenheim,20  Sadoven,21  and  Richet.22 

Accurate  studies  of  the  nitrogen  partition  in  fasting  dogs  have  been 
made  but  recently.  Previous  to  the  advent  of  Folin’s32  method  for  crea- 
tine and  creatinine  no  accurate  investigations  were  made  showing  the 
nitrogen  partition  further  than  urea  and  ammonia,  and  in  one  or  two 
cases  the  excretion  of  some  of  the  pathological  constituents  of  the  urine. 

Osterberg  and  Wolf33  report  the  nitrogen  partition  in  an  experiment 
in  which  a dog  was  fed  a low  protein  diet  for  a number  of  days  and  was 
then  given  a large  amount  of  casein,  after  which  the  animal  was  fasted. 
Their  findings  cannot  be  considered  normal  nitrogen  partition  data  for 
a fasting  dog,  inasmuch  as  the  ingestion  of  a large  amount  of  protein 
following  a low  protein  diet  would  influence  the  nitrogen  partition  of  the 
succeeding  fasting  days.  Underhill  and  Kleiner34  report  findings  upon 
the  nitrogen  partition  in  the  urine  of  a fasting  dog.  Their  experiment 
extended  over  a period  of  fourteen  days,  water  being  taken  in  varying 
amounts.  Their  results  upon  the  nitrogen  distribution  during  fasting 
as  compared  with  a well  fed  animal  show  (1)  “A  slightly  increased  per- 
centage of  ammonia  nitrogen  and  a correspondingly  diminished  urea 
percentage.”  (2)  “The  total  creatinine  nitrogen  does  not  bear  a strict 
relation  to  the  total  nitrogen” “nor  is  the  quantity  excreted  con- 

stant.” “ The  relatively  large  output  of  creatin  is  also  of  special  interest 
although  its  significance  at  this  time  is  obscure.”  They  report  the  pres- 
ence of  allantoin  in  the  urine  and  also  allantoin  crystals  in  the  urine 
after  standing,  and  hold  that  the  presence  of  this  substance  in  “ the  urine 
of  starving  dogs  shows  without  question  that  allantoin  may  have  an 
endogenous  origin.”  With  regard  to  the  purine  and  allantoin  excretion 


FASTING  STUDIES. 


7 


they  say  that:  “In  inanition  no  fixed  relationship  appears  to  exist  be- 
tween the  excretion  of  purine  and  allantoin.” 

Schondorf,35  working  with  a fasting  dog,  shows  that  the  percentage 
of  urea  nitrogen  may  fall  as  low  as  75  per  cent,  of  the  total  nitrogen. 

Leffmann36  reports  results  which  show  that  the  creatine  and  creatinine 
excretions  are  fairly  constant  for  animals  of  equal  body  weight,  and  that 
creatine  or  creatinine  ingested  with  food,  by  a well-nourished  dog,  are 
seemingly  excreted  as  such.  Weber37  shows  that  in  fasting  dogs  as  a 
result  of  muscular  activity  creatinine  is  excreted,  while  with  uniformly 
nourished  animals  creatinine  diminishes.  Dorner38  showed  that  fasting 
had  no  influence  upon  the  excretion  of  creatinine  in  rabbits  but  that 
creatine  appeared  in  increasing  amounts.  Bohtlingk39  gives  results 
upon  the  nitrogen  distribution  in  fasting  cats  and  rabbits. 

The  more  recent  work  upon  fasting  which  deals  with  the  occurrence 
of  creatine  and  creatinine  has  been  presented  by  van  Hoogenhuyze  and 
Verploegh,40  Benedict,41  Benedict  and  Diefendorf,42  and  Cathcart,43 
who  report  results  which  are  in  general  quite  similar,  the  creatinine  remain- 
ing fairly  constant,  with  a slight  decrease  as  the  fast  progresses.  The 
appearance  of  creatine  in  increasing  amounts  is  reported  by  all  except 
van  Hoogenhuyze  and  Verploegh,  who  did  not  determin  creatine.  Bene- 
dict and  Diefendorf  report  a decrease  in  creatine  after  the  rise. 

Results  upon  single  prolonged  fasts  in  the  case  of  dogs  have  been  re- 
ported by  the  following  investigators:  Howe,  Mattill  and  Hawk,23  Falck,24 
Kumagawa  and  Miura,25  Pfliiger,26  Daddi,27  Grandis,28  Krawkaw,29 
L’abbe  and  Vitry30  and  Luciani  and  Bufalini.31  The  longest  normal 
single  fast  has  been  reported  by  Howe,  Mattill,  and  Hawk.23  In  this 
prolonged  fast  the  animal  fasted  1 1 7 days,  during  which  time  he  received 
a constant  water  ingestion.  The  next  longest  normal  fast  upon  which 
data  are  presented  was  reported  by  Falck.24  This  fast  was  continued 
for  60  days.  Kumagawa  and  Miura25  report  a fast  of  98  days  during 
which  time  the  dog  was  subjected  to  repeated  doses  of  phlorhizin.  This 
fast  cannot  be  compared  with  true  fasts  because  the  phlorhizin  intro- 
duces unknown  factors. 

Description. 

Purpose  and  Plan. — The  purpose  of  this  investigation  was  to  study 
the  effect  of  repeated  fasting  upon  the  nitrogen  partition  in  the  urine 
of  a dog.  Changes  in  body  weight  were  also  observed.  As  a basis  of 
comparison  the  nitrogen  partition  of  the  urine  was  determined  during 
a normal  feeding  period  for  a number  of  days  preceding  the  fast. 

The  plan  of  the  experiment  was  as  follows : The  dog  was  brought  into 
nitrogen  equilibrium  and  then  permitted  to  fast,  the  fast  continuing 
until  the  inception  of  the  premortal  rise.  At  this  time  the  animal  was 
fed,  the  feeding  continuing  until  the  dog  had  regained  its  original  body 


8 


FASTING  STUDIES. 


weight  and  was  again  in  nitrogen  equilibrium.  Following  this  came 
the  second  fast. 

Subject. — The  animal  used  in  this  experiment  was  a small  fox-terrier 
bitch,  from  one  to  two  years  old  and  weighing  3.41  kilograms  (see  Table 

V,  p.  40).  She  was  in  good  physical  condition,  well  muscled,  and  had 
a medium  layer  of  fat  under  the  skin.  Life  in  the  experimental  cage 
did  not  seem  to  annoy  her  in  any  way. 

Articles  of  Diet:  Meat. — The  meat  fed  was  beef,  which  had  been  prepared 
according  to  the  method  proposed  by  Gies44  and  modified  by  Hawk.45 
This  method  of  preparation  and  preservation  consisted  in  freeing  the 
meat  from  as  much  visible  fat  and  connective  tissue  as  possible.  The 
trimmed  meat  was  ground  three  times  in  a sausage  mill,  using  a smaller 
plate  each  time.  The  meat  was  passed  through  the  mill  and  mixed  thor- 
oughly between  each  grinding.  This  insured  a uniform  sample.  After 
the  juices  had  been  pressed  out  of  the  meat,  it  was  sampled  and  then 
wrapped  in  paraffin  paper  in  cakes  of  about  400  to  600  g.,  placed  in  a 
museum  jar,  frozen  and  kept  in  cold  storage.  This  method  of  preser- 
vation was  very  satisfactory.  The  meat  remained  sweet,  and  after  a 
period  of  six  months  the  composition  as  regards  the  nitrogen  content 
was  practically  the  same.  The  analysis  of  the  meat  at  the  time  of  prepara- 
tion showed  3.62  per  cent,  nitrogen  and  after  a period  of  six  months 
showed  3.69  per  cent,  nitrogen,  or  on  a moisture-free  basis  when  prepared 
4.88  per  cent.;  and  after  six  months  4.86  per  cent,  of  nitrogen  (see  Table 

VI,  p.  41). 

Cracker  Dust. — Cracker  dust  was  purchased  already  ground  from 
the  manufacturer.  This  was  thoroughly  mixed,  sampled,  analyzed, 
and  kept  in  air-tight  jars. 

Lard. — Pure  leaf  lard  was  used. 

Bone  Ash. — A good  quality  of  finely  ground  bone  ash  was  used. 

Water. — Ordinary  distilled  water  was  used,  such  as  is  supplied  to  the 
chemical  laboratory. 

Method  of  Collection  and  Preservation  of  Excreta , etc. — The  animal  was 
kept  in  an  experimental  cage  such  as  described  by  Gies46  and  modified 
by  Hawk.45  This  cage  was  provided  with  a wire  netting  bottom  of  about 
3/8  inch  mesh.  Below  this  wire  bottom,  upon  which  the  animal  stands, 
there  is  arranged  a sliding  pan,  having  sides  which  slope  at  an  angle  of 
about  thirty  degrees.  An  opening  was  provided  at  the  lowest  point 
through  which  the  urine  might  pass  into  a graduated  receptacle  hung 
from  the  bottom.  With  such  a cage  the  urine  and  feces  could  be  collected 
separately,  the  urine  flowing  into  the  receiver  as  soon  as  passed,  where 
it  was  preserved  by  means  of  thymol.  The  feces  which  were,  in  the  feeding 
periods,  hardened  by  means  of  the  ingested  bone  ash  remained  on  the 
wire  netting  and  were  picked  out  with  a pair  of  forceps.  The  hair  and 


FASTING  STUDIES. 


9 


scurf  fell  through  the  netting  to  the  pan  and  were  brushed  off  each 
day.  At  the  end  of  each  period  the  whole  cage  was  carefully  washed. 
The  cage  washings  consisted  of  scurf  and  small  quantities  of  soft  feces 
which  had  fallen  through  the  netting. 

The  urine  was  collected  in  24-hour  periods  and  kept  in  tincture-mouth 
glass  bottles,  with  ground  glass  stoppers.  The  dog  was  not  catheterized 
for  it  was  found  that  when  the  animal  was  allowed  to  urinate  at  will 
the  bladder  was  satisfactorily  emptied  each  day,  or  if  a portion  of  the 
dog’s  urine  was  retained  this  was  a fairly  constant  quantity.  An  ex- 
amination of  Table  I,  page  30,  shows  that  the  urine  volumes  were  as  a 
rule  very  close  to  250  cc.  per  day,  corresponding  to  a daily  water  ingestion 
of  250  cc.  The  other  factors,  such  as  the  formation  of  water  in  metabolism 
and  loss  through  respiration,  would  seem  to  compensate  each  other. 
Thymol  and  refrigeration47  were  used  as  a means  of  preservation. 

The  feces  were  collected  when  passed,  dried,  pulverized  and  the  hair 
separated,  after  which  the  feces  were  analyzed.  Analyses  were  made 
in  periods.  The  hair,  scurf,  and  cage  washings  were  also  analyzed  in 
periods  and  the  nitrogen  distributed  evenly  according  to  the  number  of 
days  in  the  period  (see  Table  VI,  p.  41). 

The  dog  was  weighed  on  a platform  balance  which  was  accurate  to  0.0 1 
kilogram. 

Analyses  and  Methods. — Total  nitrogen,  urea,  creatine,  creatinine, 
allantoin,  and  purine  determinations  were  made  upon  the  urine,  and  total 
nitrogen  determinations  upon  the  feces,  hair  and  cage  washings.  All 
urine  analyses  were  made  in  duplicate  and  upon  the  24-hour  sample,  ex- 
cept for  a part  of  the  intermediate  feeding  period,  when  analyses  were 
made  on  two-day  composit  samples  and,  in  the  case  of  allantoin  and 
purine,  which  were  determined  in  composit  samples  of  from  two  to  ten 
days. 

The  total  nitrogen  was  determined  by  the  Kjeldahl  method,  copper 
sulfate48  being  used  in  the  preliminary  oxidation. 

The  urea  was  determined  by  the  Benedict-Gephart49  modification 
of  the  Folin50  method.  While  this  method  has  recently51  been  shown 
to  be  slightly  inaccurate,  due  to  the  partial  decomposition  of  uric  acid, 
creatine,  creatinine,  allantoin,  and  hippuric  acid,  still  these  substances 
occur  in  such  small  amounts  in  the  urine  of  the  dog  that  the  urea  results 
may  be  accepted  as  a fairly  accurate  indication  of  the  amount  of  urea 
present  in  the  urine.  Ammonia  was  determined  by  the  method  described 
by  Folin.52  Creatinine  was  also  determined  by  the  Folin32  procedure. 
The  creatine  was  hydrolyzed  in  the  autoclave  as  suggested  by  Benedict 
and  Meyers.53  Allantoin  and  purine  were  determined  upon  the  same 
composit  sample  by  the  method  suggested  by  Poduschka,54  and  modi- 
fied by  Underhill  and  Kleiner.34 


IO 


FASTING  STUDIES. 


Blank  determinations  were  made  in  all  cases  where  possible  impurities 
in  the  reagents  might  cause  an  error. 

EXPERIMENTAL. 

Preliminary  Feeding  Period. 

In  an  investigation  of  this  character  in  which  the  nitrogen  distribution 
is  the  subject  under  consideration  it  is  important  that  there  shall  be  a 
preliminary  period.  During  this  time  the  subject  will  live  under  the 
same  conditions  as  those  which  will  exist  during  the  experiment  proper, 
and  will  receive  a constant  diet.  In  our  case,  in  addition  to  obtaining 
uniform  conditions  of  living  and  diet,  this  period  served  to  put  the  animal 
in  a condition  of  nitrogen  equilibrium,  and  also  to  furnish  data  for  the 
nitrogen  partition  of  the  urine  of  the  animal  under  these  normal  conditions, 
and  thus  serve  as  a basis  of  comparison  for  the  fasting  and  for  the  in- 
termediate feeding  periods. 

The  preliminary  feeding  period  in  this  experiment  extended  over  fif- 
teen days.  At  the  end  of  this  time,  during  which  the  animal  had  received 
a uniform  diet  and  constant  water  ingestion,  a uniform  body  weight 
had  been  secured  and  the  dog  was  in  nitrogen  equilibrium.  At  this 
point,  the  nitrogen  balance  showed  an  average  of  — 0.271  gram  of  nitrogen 
per  day  for  the  eight  days  immediately  preceding  the  fast.  The  nitro- 
gen partition  in  the  urine  was  determined  for  this  period.  The  diet  con- 
sisted of  70  grams  of  meat,  15  grams  of  cracker  dust,  8 grams  of  lard, 
3 grams  of  bone  ash,  and  250  cc.  of  water.  See  Table  VI,  p.  41. 
These  ingredients  were  thoroughly  mixed  together  and  fed  in  the  form 
of  a broth.  This  diet  contained  2.732  grams  of  nitrogen,  or  about  0.8 
gram  per  kilogram  body  weight. 

The  data  of  the  preliminary  period  are  found  in  Tables  I and  IV,  pp.  30 
and  36.  From  a consideration  of  the  average  data  for  this  period  it  will 
be  seen  that  with  an  ingestion  of  2.732  grams  of  nitrogen  per  day  the  dog  ex- 
creted 2.762  grams  of  nitrogen  in  the  urine,  and  suffered  a further  loss  of 
0.235  gram  of  nitrogen  in  the  form  of  feces,  hair  and  cage  washings. 
This  gives  a minus  balance  of  0.271  gram  of  nitrogen  per  day.  This 
is  an  approximate  nitrogen  equilibrium  (see  Table  IV,  p.  36). 

First  Fast. 

At  the  end  of  the  preliminary  period  the  dog  was  in  a fair  nitrogen 
equilibrium,  and  had  maintained  a constant  body  weight  for  three  days. 
The  last  food  was  given  at  2 p.m.,  Feb.  4th,  and  the  fast  was  considered 
as  beginning  at  2 p.m.,  Feb.  5th,  the  urine  collected  at  2 p.m.  on  Feb. 
6th  being  considered  as  representing  the  urine  of  the  first  day  of  fast. 
On  the  first  day  the  water  (250  cc.)  was  placed  in  the  food  pan,  but  only 
50  cc.  were  taken.  As  a result  the  urine  volume  for  the  first  day  was 
only  35  cc.  and  this  was  combined  with  the  urine  of  the  following  day.  When 


FASTING  STUDIES. 


1 1 

the  dog  refused  water  on  the  second  day  of  fast,  the  fluid  was  given  by 
means  of  a tube  and  this  was  continued  throughout  the  fasts.  On  the 
seventh  day  the  first  feces  were  passed,  which  were  very  small  in  amount 
and  of  a pasty  consistency.  On  the  eleventh  day  the  second  fasting 
feces  were  passed;  these  feces  were  removed  from  the  cage  immediately 
after  defecation  and  were  greenish-brown  in  color,  becoming  black  upon 
exposure  to  air.  It  seems  probable  that  the  fresh  fasting  feces  of  the 
dog  are  of  a greenish-brown  cast  and  only  assume  the  black  color  ordi- 
narily ascribed  to  them55  upon  coming  in  contact  with  the  air.  More 
fasting  feces  were  passed  on  the  thirteenth  day  of  fast.  The  dog  con- 
tinued weaker  and  could  hardly  stand.  Feces  were  again  passed  on 
the  fourteenth  day,  but  in  small  amount. 

The  lower  nitrogen  percentages  for  the  feces  of  the  feeding  periods 
above  those  for  the  fasting  periods  (see  Table  VI,  p.  41)  is  probably 
due  primarily  to  the  fact  that  bone  ash  was  used  in  the  diet  of  the  feeding 
period  thus  increasing  the  bulk  of  the  fecal  output  although  having  no 
influence  upon  its  nitrogen  content.  At  the  same  time  it  is  no  doubt 
true  that  under  some  conditions  at  least,  the  percentage  of  nitrogen  in 
fasting  feces  is  higher  than  that  of  the  feeding  feces  from  the  same  animal.1 

The  following  entry  was  made  in  the  diary  at  the  close  of  the  fifteenth 
day  of  fast.  “February  20th.  Soft  feces  in  a.m.  Dog  could  not  stand 
and  was  in  an  extremely  weak  condition.  Pulse  rose  from  54,  yesterday, 
to  140  to-day,  and  the  temperature  sank  from  370  to  36°.  Weight 
fell  from  2.05  kg.  to  1.85  kg.  She  has  lost  over  40  per  cent,  of  her  body 
weight  in  two  weeks.  A very  striking  loss.  Dog  was  so  weak  we  feared 
to  go  further,  therefore,  we  fed  her  (4  p.m.)  15  grams  cracker  dust,  2 
grams  bone  ash,  and  3 grams  lard.  She  took  one-half  of  it.  Gave  her  re- 
mainder of  it  in  the  evening  and  covered  her  up  with  a blanket  to  keep  her 
warm.  Pier  nose  was  cold.  She  wagged  her  tail  when  addressed,  could  not 
stand,  however  (6.10  p.m.).  After  dinner  the  dog  rose  as  we  entered  and 
walked  to  the  front  of  the  cage,  wagging  her  tail.  She  was  a new  dog,  and  yet 
she  had  partaken  of  only  about  8 grams  of  cracker  dust,  3 grams  of  lard, 
and  2 grams  of  bone  ash.  We  fed  her  the  remainder  of  the  amount  of 
food,  previously  mentioned,  and  then  fixed  her  blanket  for  her  in  the 
corner  of  the  cage  and  she  lay  down  contentedly.  Later  in  the  evening 
the  dog  seemed  much  stronger.” 

Discussion  of  the  Nitrogen  Distribution  for  the  First  Fast.  Total  Nitro- 
gen.— From  an  examination  of  Table  I,  p.  30,  and  of  figure  on  p.  12,  it  is 
seen  that  in  the  first  two  days  the  nitrogen  excretion  fell  from  an  average 
of  2.768  grams  during  the  preliminary  period,  to  an  average  of  1.3 17 
grams.  This  low  nitrogen  excretion  is  due,  as  has  been  proven  by  Bene- 
dict41 in  fasts  upon  men,  to  the  sparing  action  of  glycogen  present  in  the 
1 Unpublished  results  from  this  laboratory. 


REPEATTD  FAST  • i DOGNsI 


FASTING  STUDIES. 


13 


body.  After  the  second  day  the  nitrogen  excretion  in  the  urine  rose  rapidly 
from  day  to  day,  taking  a slight  drop  during  the  twelfth  to  fourteenth 
days,  and  followed  by  a pronounced  premortal  rise,  the  nitrogen  output 
increasing  from  2.472  grams  on  the  fourteenth  day  to  3.944  grams  on  the 
fifteenth  day. 

The  rapidly  increasing  output  of  nitrogen  mentioned  above  as  occurring 
during  the  first  twelve  days  of  the  fast  is  somewhat  unusual.  It  might 
be  inferred  from  such  data,  according  to  the  commonly  accepted  theories 
with  regard  to  the  nitrogen  excretion  in  the  urine  of  a fasting  dog,  that 
the  animal  was  thin  and  muscular,  without  any  fat  stores  of  any  amount. 
Or,  on  the  other  hand,  it  might  be  argued  that  the  dog  was  organically 
unsound.  We  believe  both  premises  to  be  unfounded  and  have  dis- 
cussed the  matter  more  at  length  on  p.  22. 

Urea. — The  excretion  of  nitrogen  as  urea  followed  the  total  nitrogen 
excretion,  increasing  absolutely,  but  not  relatively.  The  percentage 
urea  nitrogen  as  compared  with  the  total  nitrogen  was  practically  con- 
stant throughout  the  fast,  the  average  being  89.13  per  cent,  (see  Table 
III,  p.  36)  and  the  range  being  86.36  per  cent,  on  the  sixth  day  to  91.12 
per  cent,  on  the  seventh  day  (see  Table  II,  p.  34).  This  average  ex- 
cretion is  slightly  higher  than  that  found  in  the  normal  feeding  period 
(86.79  Per  cent.). 

This  constant  relation  between  urea  and  total  nitrogen  is  contrary  to 
the  statements  in  the  literature,  33»  34>  35  to  the  effect  that  the  percentage 
of  nitrogen  as  urea  nitrogen  decreases  as  the  fast  progresses.  This  fact 
holds  for  men23'  41>  43  but  it  does  not  seem  to  hold  for  the  dog,  as  is  shown 
in  the  experiments  reported  from  our  laboratory  by  Howe,  Mattill  and 
Hawk.  In  their  results  the  variations  did  not  tend  in  any  marked  di- 
rection away  from  a constant  relative  value. 

The  fact  that  the  method  of  determining  the  urea-nitrogen  is  not 
absolutely  accurate  might  appear  to  invalidate  our  deductions.  How- 
ever, if  the  method  determined  all  of  the  nitrogen  appearing  as  creatine, 
creatinine,  etc.,  the  percentage  of  nitrogen  as  urea  would  not  be  reduced 
more  than  3 to  4 per  cent,  and  this  would  be  a fairly  constant  quantity 
throughout  the  experiment.  Therefore,  this  error  does  not  detract  from 
the  accuracy  of  our  conclusions. 

Ammonia. — The  ammonia-nitrogen  fell  from  the  average  excretion 
per  day  of  0.143  gram  of  nitrogen  during  the  feeding  period  to  an  average 
of  0.103  gram  per  day  during  the  fast.  After  the  first  four  days  the  am- 
monia excretion  remained  almost  constant,  rising  slightly  at  the  end, 
with  the  premortal  rise.  The  relative  excretion  increased,  then  fell, 
and  finally  increased  again  to  the  end.  The  range  in  the  percentage  of 
ammonia  nitrogen  as  compared  to  total  nitrogen  was  from  3.64  per  cent, 
on  the  ninth  day,  to  6.24  per  cent,  on  the  third  day,  the  average  per  cent. 


H 


FASTING  STUDIES. 


of  total  nitrogen  appearing  as  ammonia  nitrogen  being  4.59  per  cent, 
(see  Table  II,  p.  34,  and  Table  III,  p.  36). 

Creatinine. — The  creatinine  decreased  in  absolute  amount  very  gradually 
with  but  slight  variations  from  day  to  day.  The  average  daily  excretion 
for  the  fast  (0.025  gram  of  nitrogen)  was  below  that  of  the  feeding  period 
(0.041  gram  of  nitrogen).  This  pronounced  drop  took  place  during  the 
first  part  of  the  fast  and  from  then  on  the  absolute  amount  of  creatinine 
excreted  per  day  fell  gradually,  following  in  general  the  decreasing  body 
weight.  While  the  absolute  amount  of  creatinine  nitrogen  fell  very  grad- 
ually, the  percentage  output  decreased  much  more  rapidly.  The  per- 
centage of  total  nitrogen  appearing  as  creatinine  was  2.28  per  cent,  for 
the  first  two  days,  and  then  fell  very  regularly,  as  the  fast  progressed, 
to  0.46  per  cent,  on  the  last  day.  The  grand  average  was  1.14  per  cent, 
as  against  an  average  of  1.49  per  cent,  for  the  normal  feeding  period 
(see  Table  II,  p.  34,  and  Table  III,  p.  36). 

Creatine. — The  creatine  nitrogen  fell  from  the  feeding  level  (daily  average 
of  0.056  gram  of  nitrogen)  to  an  average  of  0.018  gram  for  the  first  two 
days,  and  then  remained  approximately  equal  to  the  amount  of  crea- 
tinine nitrogen  excreted,  being  in  general  somewhat  below  this  value. 
On  the  ninth  day  the  amount  of  creatine  nitrogen  excreted  rose  very 
suddenly  from  0.037  gram  to  0.054  gram>  and  continued  on  this  higher 
plane,  with  a tendency  toward  an  increasing  excretion,  to  the  end  of  the 
fast.  The  average  excretion  for  these  two  portions  of  the  fast  were 
0.025  gram  of  nitrogen  for  the  first  eight  days  and  0.068  gram  of  nitro- 
gen for  the  last  seven  days,  with  a grand  average  of  0.046  gram  of  nitro- 
gen. 

The  percentage  of  total  nitrogen  as  creatine  nitrogen  increased  from 
1.40  per  cent,  on  the  first  day  to  3.10  per  cent,  on  the  twelfth  day,  due 
to  the  greatly  increased  nitrogen  excretion.  The  average  percentage 
of  total  nitrogen  was  1.94  per  cent,  against  2.01  per  cent,  for  the  feeding 
period  (see  Table  II,  p.  34,  and  Table  III,  p.  36). 

Allantoin  and  Purine.1 — The  allantoin  and  purine  nitrogen  varied 
from  day  to  day.  The  average  purine  nitrogen  excretion  was  below  that 
of  the  feeding  period,  being  0.005  gram  per  day,  for  eleven  days  of  the 
fast,  against  0.012  gram  of  nitrogen  during  the  feeding  period.  The 
same  average  amount  of  allantoin  nitrogen  as  of  purine  nitrogen  was  ex- 
creted, i.  e.y  0.005  gram  while  there  was  0.008  gram  of  allantion  nitrogen 
excreted  per  day,  during  the  feeding  period. 

The  relative  amounts  of  nitrogen  excreted  as  purine  and  allantoin 
nitrogen  were  0.22  per  cent,  of  purine,  and  0.26  per  cent,  of  allantoin 
nitrogen,  while  the  feeding  period  gave  0.45  per  cent,  purine,  and  0.31 
per  cent,  allantoin  nitrogen  (see  Table  II,  p.  34,  and  Table  III,  p.  36). 

1 These  determinations  were  made  by  Mr.  S.  R.  Wreath. 


FASTING  STUDIES. 


5 


Undetermined  Nitrogen. — The  undetermined  nitrogen  fell  as  a result 
of  the  fast,  being  0.067  gram  for  an  average  during  the  fast,  against 
0.109  gram  for  the  feeding  period. 

Intermediate  Feeding  Period. 

General  Considerations. — The  object  of  this  feeding  period  was  to  re- 
store the  animal  to  its  original  condition  as  regards  body  weight  and 
nitrogen  equilibrium.  The  data  upon  the  income  and  outgo  of  nitrogen 
are  found  in  Tables  I and  IV,  pp.  30  and  36.  During  the  portion  of  the 
feeding  period  immediately  following  the  end  of  the  first  fast  the  diet 
was  varied.  The  same  constituents  were  fed,  but  the  animal  did  not 
receive  the  full  diet  given  in  the  preliminary  period.  The  diet  for  the 
first  three  days  did  not  contain  any  meat,  and  there  was  a minus  balance 
of  3 grams  for  this  period.  A positive  balance  of  1.218  grams  occurred 
on  the  fourth  day,  when  meat  was  fed  for  the  first  time.  During  this 
preliminary  period  of  four  days  on  an  extremely  low  diet,  the  animal 
gained  21.08  per  cent,  in  body  weight.  The  original  diet  was  then  fed, 
and  continued  for  fifteen  days,  during  which  period  the  body  weight 
increased  but  7.57  per  cent.  In  fact,  during  the  last  three  days  of  this 
period  there  was  practically  no  increase  in  weight. 

It  appeared  that  to  restore  the  original  body  weight,  on  the  normal 
diet,  would  require  a very  long  time,1  hence  the  diet  was  increased  50 
per  cent,  thus  causing  the  dog  to  ingest  4.104  grams  of  nitrogen  per  day. 
Upon  this  diet  the  dog  gained  20  per  cent,  of  its  weight  in  eight  days. 
The  diet  was  again  increased  50  per  cent,  at  the  end  of  the  eight-day 
period  of  increased  feeding.  The  animal  was  now  receiving  twice  as 
much  nitrogen  per  day  (5.464  grams  of  nitrogen)  as  was  required  to  main- 
tain her  constant  body  weight  at  the  beginning  of  the  experiment. 
Throughout  these  periods  of  increased  diet  (50  per  cent,  and  100  per 
cent.)  the  animal  showed  a plus  nitrogen  balance.  After  seventeen 
days  of  the  100  per  cent,  increase  the  dog  had  more  than  regained  the 
weight  lost  during  fasting,  the  weight  being  3.59  kilograms,  against  a 
weight  of  3.41  kilograms  at  the  beginning  of  the  fast.  The  diet  was  now 
reduced  to  the  normal  (2.732  grams  of  nitrogen  per  day).  The  weight 
dropped  slightly  on  the  first  day,  and  remained  constant  for  the  following 
two  days  at  3.54  kilograms  and  at  the  same  time  the  dog  was  in  nitrogen 
equilibrium,  there  being  a plus  balance  of  0.02  gram  of  nitrogen  per 
day. 

1 That  it  was  possible  to  restore  the  normal  body  weight  of  fasting  rabbits  which 
were  fed  the  original  diet  following  the  breaking  of  the  fast,  has  been  shown  by  Kagan.® 
However,  in  these  tests  the  animals  were  not  brought  into  a condition  of  nitrogen  equi- 
librium before  being  fasted,  and  the  original  diet  may  therefore  have  been  an  excessive 
one,  thus  enabling  Kagan  to  restore  the  normal  weight  of  his  rabbits  with  greater 
facility  than  otherwise. 


i6 


FASTING  STUDIES. 


In  spite  of  the  fact  that  the  dog  was  giving  a minus  balance  during  the 
first  three  days  of  the  feeding  period  she  gained  280  grams  in  weight. 
This  may  have  been  due  to  the  retention  of  water,  for  although  the  dog 
had  been  receiving  250  cc.  of  water  daily  throughout  the  fast,  upon  feed- 
ing the  urine  volumes  for  the  first  two  days  decreased  to  215  and  50  cc. 
respectively.  While  the  method  of  collecting  the  urine  (without  catheteri- 
zation) does  not  give  absolute  values  for  the  urine  volumes,  the  values 
indicate  that  there  must  have  been  a marked  water  retention  upon  the 
ingestion  of  food.  This  has  been  previously  noted  in  feeding  after  ab- 
solute fasts  in  dogs,9  and  also  with  men,23  who  had  been  receiving  water 
during  the  fast. 

Nitrogen  Distribution. — The  average  relative  amount  of  urea  nitrogen 
excreted  increased,  as  would  be  expected,  with  the  increase  in  the  diet, 
and  the  amount  of  nitrogen  excreted  per  day.  The  percentage  nitrogen 
output  as  urea  dropped  to  the  level  of  the  preliminary  period  upon  the 
resumption  of  the  normal  diet.  For  further  discussion  see  p.  23. 

The  absolute  amount  of  ammonia  nitrogen  increased  with  the  in- 
crease in  the  diet.  The  relative  amount  of  ammonia  decreased,  how- 
ever, and  was  equal  to  the  normal  upon  return  to  the  original  diet. 

The  creatinine  nitrogen  increased  from  day  to  day  corresponding  to 
the  increase  in  muscular  tissue.  The  average  amount  of  creatinine  ex- 
creted upon  return  to  the  original  condition  and  body  weight  at  the  end 
of  the  intermediate  feeding  period  was  practically  equal  to  that  excreted 
under  the  normal  conditions  in  force  at  the  end  of  the  preliminary  feeding 
period,  being  0.040  gram  of  nitrogen  per  day,  against  0.041  gram.  Rela- 
tively, however,  the  creatinine  excretion  decreased  with  the  increase  in 
diet  and  the  amount  of  total  nitrogen  excreted.  On  the  same  diet  (nor- 
mal) the  creatinine  nitrogen  excretion  was  1.49  per  cent,  of  the  total 
nitrogen,  during  the  preliminary  feeding  period,  whereas,  at  the  end  of 
the  intermediate  feeding  period,  the  value  was  1.63  per  cent.  In  each 
case  the  dog  was  in  nitrogen  equilibrium  and  of  practically  the  same 
body  weight. 

The  amount  of  creatine  nitrogen  excreted  increased  with  the  increase 
in  the  quantity  of  meat  fed.71  In  other  words  the  creatine  ingested  with 
the  food  was  in  part  excreted  in  the  urine. 

Allantoin  and  purine  nitrogen  were  both  excreted  in  larger  amounts 
during  the  fasting  period.  The  average  purine  nitrogen  excretion  was 
less  (0.008  gram)  than  that  in  the  preliminary  feeding  period  (0.012 
gram),  whereas  the  allantoin  nitrogen  was  the  same,  i.  e.,  0.008  gram. 

Second  Fast. 

At  the  end  of  the  feeding  period,  the  weight  of  the  animal  was  constant, 
within  20  grams,  for  a period  of  six  days.  At  the  beginning  of  the  second 
fast  the  body  weight  was  constant,  although  a little  higher  (3.54  kilograms) 


FASTING  STUDIES. 


17 


than  at  the  beginning  of  the  first  fast  (3.41  kilograms).  The  nitrogen 
balance  was  +0.02  gram  on  the  day  preceding  the  fast.  The  animal 
appeared  to  be  in  a much  better  physical  condition  than  when  brought 
to  nitrogen  equilibrium  at  the  beginning  of  the  first  fast.  The  coat  was 
much  smoother  and  the  muscles  were  very  firm.  The  activity  and  at- 
tentiveness were  fully  as  pronounced  as  at  the  beginning  of  the  first 
fast. 

The  last  food  was  given  at  2 p.m.  on  April  7th  and  the  urine  collected 
on  April  9th  was  taken  as  the  first  fasting  urine.  In  this  fast  the  water 
(250  cc.  per  day)  was  given  entirely  by  means  of  a tube.  Signs  of  marked 
weakness  did  not  appear  until  about  the  fourteenth  fasting  day,  and 
even  then  the  dog  was  quite  active.  From  then  on  she  became  grad- 
ually weaker,  becoming  more  quiet  and  less  disposed  to  move  about. 
She  became  perceptibly  weaker  on  the  twenty-ninth  day  and  at  6.15 
a.m.  on  the  thirtieth  day  of  the  fast  (16  hours  after  the  beginning  of 
that  day)  the  dog  was  found  lying  upon  her  side  in  a state  of  coma.  Par- 
ticulars with  regard  to  the  post-mortem  examination  and  the  histological 
characteristics  of  the  tissues  will  be  published  in  a later  article. 

Total  Nitrogen. — The  analytical  data  for  the  second  fast  are  contained 
in  Table  I,  p.  32,  and  the  data  are  represented  graphically  in  figure  on 
p.  12.  From  an  excretion  of  2.435  grams  on  the  last  day  of  the  feeding 
period,  the  total  nitrogen  excretion  dropped  on  the  first  day  of  fast  to 
1. 08 1 grams.  This  was  the  smallest  twenty-four-hour  output  of  nitrogen 
excreted  at  any  time  during  the  progress  of  the  fast.  The  nitrogen  excre- 
tion remained  fairly  constant  for  the  first  twenty-six  days.  The  maxi- 
mum for  this  time  was  1.471  grams  on  the  sixth  day  (when  no  water  was 
given)  with  an  average  of  1.23 1 grams.  From  the  twenty-sixth  day  on 
there  was  an  increased  nitrogen  excretion  from  day  to  day,  until  on  the 
thirtieth  day  an  output  of  2.298  grams  was  registered  for  a sixteen-hour 
period. 

Urea. — The  urea  nitrogen  excretion  followed  the  total  nitrogen.  Rela- 
tive to  the  total  nitrogen  the  average  for  the  whole  fast  was  86.51  per 
cent.,  the  extreme  values  being  76.56  per  cent,  and  90.88  per  cent,  (see 
Table  II,  p.  35,  and  Table  III,  p.  36).  The  lower  value  is  probably 
the  result  of  alkaline  fermentation,  for  the  urine  was  found  standing  on 
the  pan  of  the  cage,  the  wire  gauze  which  served  as  a filter  having  become 
clogged  with  hair.  Aside  from  three  days,  the  seventeenth,  nineteenth, 
and  twenty-third  days  of  the  fast  on  which  alkaline  fermentation  prob- 
ably occurred,  the  variation  was  between  81.95  per  cent,  and  90.88  per 
cent,  with  an  average  of  87.46  per  cent.,  there  being  no  marked  tendency 
toward  either  a drop  or  a rise  in  the  percentage  of  total  nitrogen  as  urea. 

Ammonia. — The  ammonia  nitrogen  showed  a slight  tendency  to  in- 
crease, as  the  fast  progressed,  both  absolutely  and  relatively.  However, 


i8 


FASTING  STUDIES. 


after  the  first  six  days,  the  excretion  remained  fairly  constant,  there 
being  but  slight  variations  in  either  direction  from  the  mean  (0.083  gram 
of  nitrogen).  This  mean  is  a little  high  for  it  includes  the  three  days 
on  which  alkaline  fermentation  probably  took  place,  and  also  the  last 
two  days  when  the  ammonia  excretion  was  high.  Excluding  these, 
the  average  was  0.068  gram  of  nitrogen.  The  variations  noted  range 
from  0.039  gram  to  0.085  gram  of  ammonia  nitrogen. 

Creatinine. — The  creatinine  nitrogen  fell  gradually  from  0.032  gram  on 
the  first  day  to  0.012  gram  on  the  twenty-sixth  day,  with  slight  varia- 
tions which  may  be  attributed  to  the  method  of  urine  collection  (without 
catheterization).  Unfortunately  through  accident  we  were  prevented 
from  obtaining  creatine  and  creatinine  data  on  the  urine  for  the  last  three 
days  of  fast.  The  excretion  of  nitrogen  as  creatinine  decreased,  from  day 
to  day,  both  absolutely  and  relatively.  The  maximum  output  was 
2.96  per  cent,  on  the  first  day,  and  the  minimum  0.94  per  cent,  on  the 
twenty-seventh  day,  of  fast,  the  average  being  1.85  per  cent,  (see  Table 
II,  p.  35,  and  Table  III,  p.  36). 

Creatine. — The  creatine  nitrogen  fell  below  that  of  the  creatinine  and 
remained  fairly  constant  until  the  fifteenth  day,  when  it  became  greater 
than  the  creatinine  excretion,  and  remained  above  this  value  to  the  end  of 
the  fast.  On  the  last  two  days  on  which  creatine  was  determined,  there  was 
a tendency  toward  a rise  in  the  creatine  nitrogen  excretion  corresponding 
to  the  premortal  rise.  The  average  creatine  excretion  was  0.026  gram 
of  nitrogen  per  day,  the  extremes  being  0.008  gram  on  the  fourteenth 
day,  and  0.053  gram  on  the  twenty-seventh  day  of  fast.  Relative  to 
the  total  nitrogen  the  creatine  nitrogen  excreted  was  an  average  of  2.05 
per  cent,  with  extremes  of  0.68  per  cent,  on  the  fourteenth  day  and  3.64 
per  cent,  on  the  twenty-sixth  day  (see  Table  II,  p.  35,  and  Table  III, 
P-  36). 

Allantoin  and  Purine. — The  allantoin  and  purine  nitrogen  did  not  show 
any  marked  tendency  toward  a definit  variation.  The  average  excre- 
tion was  0.005  gram  of  purine  nitrogen  per  day,  and  0.004  gram  of  allan- 
toin nitrogen  per  day,  which  represents  0.38  per  cent,  of  the  total  nitro- 
gen as  purine  nitrogen,  and  0.3 1 per  cent,  as  allantoin  nitrogen,  respectively 
(see  Table  III,  p.  36). 

Undetermined  Nitrogen. — The  undetermined  nitrogen  was  low,  and 
practically  constant  in  amount  from  day  to  day.  It  is  interesting  to 
note  that  the  average  daily  amount  of  undetermined  nitrogen  in  the 
second  fast  was  only  half  that  excreted  during  the  first  fast. 

Discussion  of  the  Two  Fasts. 

Data  have  been  presented  from  two  fasts  upon  a dog,  which  had  pre- 
viously never  been  subjected  to  an  experiment  of  this  character.  The 
first  fast  continued  for  a period  of  fifteen  days,  or  until  the  dog  was  in 


FASTING  STUDIES. 


19 


a state  of  collapse  and  the  premortal  rise  was  in  evidence.  This  fast 
was  followed  by  an  intermediate  feeding  period  of  forty-seven  days,  during 
which  time  the  animal  was  restored  to  its  original  condition.  Following 
this  came  the  second  fast,  which  continued  for  thirty  days,  or  twice  as 
long  as  the  first  fast. 

Some  important  factors  which  affect  the  length  or  intensity  of  a fast 
are  the  race  or  breed,  the  age,  the  physical  condition  and  activity,  the 
surrounding  temperature,  the  character  of  the  preliminary  feeding  period, 
the  general  type  of  the  nutritional  and  metabolic  mechanism,  and  whether 
the  fast  is  absolute  or  with  water.  Since  the  two  fasts  were  to  be  com- 
pared, it  was  essential  that  the  animal  should  be  as  nearly  as  possible 
in  the  same  condition  as  regarded  body  weight,  nitrogen  equilibrium, 
etc.,  at  the  commencement  of  each  fast,  and,  that  the  experimental 
procedure  throughout  the  fasts  should  be  similarly  regulated.  The  body 
weight  and  nitrogen  equilibrium  were  chosen  as  constants  to  be  attained 
before  the  beginning  of  the  fast,  whereas  the  water  ingested  was  a constant 
for  the  whole  experiment.2  57 

In  this  experiment  breed  and  age  do  not  enter  directly.  While  the 
age  of  the  animal  affects  the  length  of  fast,  in  this  case  the  dog  was  matured 
and  the  time  between  the  two  fasts  was  so  short  (47  days)  that  the  age 
could  not  enter  in  any  material  way;  Before  each  fast  the  dog  was 
brought  to  a constant  body  weight,  and  was  practically  in  nitrogen  equi- 
librium. The  body  weight  was  a little  greater  at  the  beginning  of  the 
second  fast,  being  3.54  kilograms,  while  at  the  beginning  of  the  first 
fast  the  weight  was  3.41  kilograms.  Whether  this  increase  in  weight 
was  fat  or  muscular  tissue  will  be  discussed  later.  A lower  nitrogen 
balance  was  attained  than  before  the  first  fast,  +0.02  gram  of  nitrogen 
against  — 0.271  gram  before  the  first  fast  (see  Table  IV,  p.  37).  The 
physical  condition  of  the  animal  immediately  before  the  fasts  was  prac- 
tically the  same  in  the  two  instances.  However,  her  coat  was  smoother 
and  her  muscles  rather  firmer  at  the  commencement  of  the  second  fast. 

Under  the  conditions  outlined  above,  the  dog  experienced  two  fasts. 
That  these  were  profound  is  evidenced  by  the  presence  of  the  premortal 
rise  and  the  collapse  of  the  animal  in  each  case.  The  first  fast  was  fifteen 
days  long  while  the  second  was  twice  as  long.  These  are  seemingly  short 
fasts,  but  considering  the  size  and  age  of  the  dog  they  are  of  average 
length.  The  greater  length  of  the  second  fast  is  probably  due  to  the 
resistance  of  the  tissues  toward  breakdown,  acquired  as  a result  of  the 
first  fast.  During  the  first  fast  the  tissues  seem  to  have  broken  down 
very  readily,  so  that  the  body  lived  improvidently  upon  its  reserves. 
In  the  second  fast,  however,  the  protein  and  fat  needed  for  the  main- 
tenance of  fife  were  used  sparingly,  and,  as  a consequence,  the  dog  fasted 
longer.  This  low  rate  of  katabolism  may  have  occurred  in  one  of  two 


20 


FASTING  STUDIES. 


ways:  the  cells,  as  a result  of  the  fast  and  the  subsequent  rebuilding 
became  more  resistant,  i.  e.,  they  gave  up  their  protein  constituents 
less  readily  to  the  blood  stream,  on  the  other  hand,  the  amount  of  pro- 
tein or  energy  required  for  the  functioning  of  the  active  organs,  may 
have  been  lessened  and  consequently  the  latter  did  not  draw  upon  the 
reserve  protein  as  heavily  as  would  have  occurred  had  they  not  ex- 
perienced a previous  siege  of  fasting. 

That  the  difference  in  the  duration  of  the  fasts  was  not  a result  of  the 
amount  of  fat  stored  up  in  the  body  can  be  shown  from  consideration  of 
the  nitrogen  data  and  body  weights.  The  calculations  on  this  basis 
follow : 


Weight  before  the  first  fast 3.41  kg. 

Weight  after  the  first  fast 1.85  kg. 

Percentage  loss  in  weight 45  -75  % 

Weight  before  second  fast 3.54  kg. 

Weight  after  second  fast 1.91  kg. 

Percentage  loss  in  weight 46.04  % 

Weight  lost  during  first  fast 


Nitrogen  lost  during  first  fast,  35 . 65  gr. 

Equivalent  of  nitrogen  in  terms  of  flesh  (3.25  per  cent.  N) . . . . 

Weight  of  fat  and  water  lost  (by  difference) 

Weight  gained  during  feeding 

Nitrogen  stored  during  feeding,  38.25  gr. 

Equivalent  of  nitrogen  in  terms  of  flesh  (3.25  per  cent.  N) . . . . 

Weight  of  fat  and  water  stored  (by  difference) 

Weight  lost  during  second  fast 

Nitrogen  lost  during  second  fast,  41.15  gr. 

Equivalent  of  nitrogen  in  terms  of  flesh  (3.25  per  cent.  N) . . . . 
Weight  of  fat  and  water  lost  (by  difference) 


1560  gr. 

1100  gr. 
460  gr. 
1690  gr. 

1180  gr. 
5io  gr. 
1630  gr. 

1260  gr. 
370  gr. 


When  calculating  all  of  the  nitrogen  lost  as  flesh,  and  the  difference 
between  that  and  the  loss  in  weight  as  fat,  we  see  that  during  the  feeding 
period  the  body  increased  its  muscular  tissue  by  80  grams,  and  its  fat 
by  50  grams,  over  the  condition  existing  at  the  beginning  of  the  first 
fast.  We  can  not  say  positively  that  that  which  has  been  called  fat  in 
the  above  calculation  is  entirely  fat,  although  the  approximation  is  prob- 
ably more  accurate  in  the  case  of  muscular  tissue.  However  from  a 
consideration  of  these  data  we  may  conclude  that  the  dog  was  apparently 
in  the  same  condition  at  the  commencement  of  each  fast. 

The  increased  length  of  the  second  fast  was  not  acccompanied  by  a 
corresponding  increase  in  the  amount  of  muscular  tissue  and  fat  katabo- 
lized.  There  was  an  increase  of  about  5.5  grams  in  the  total  weight 
of  nitrogen  lost,  which  amount  was  lost  during  the  last  three  days  of  the 
fast.  The  calculations  for  the  second  fast  show  that  only  370  grams 
of  fat  were  lost,  while  510  grams  were  deposited  during  the  intermediate 
feeding  period,  leaving  140  grams  of  this  deposited  fat  in  the  body  at 


FASTING  STUDIES. 


21 


the  end  of  the  fast.  The  fact  that  the  post-mortem  examination  showed 
that  the  animal  was  almost  free  from  visible  fat  would  contradict  this 
statement,  unless  it  were  in  the  form  of  combined  fat  (phosphatides) 
as  suggested  by  MacLean  and  Williams.58 

Had  the  increased  length  of  fast  and  the  decreased  muscular  katabolism 
been  influenced  by  more  extensive  fat  deposits  a much  larger  amount 
of  fat  would  have  been  used  than  can  be  accounted  for.  It  seems  there- 
fore that  the  phenomena  were  due  to  the  altered  rate  of  the  anabolic 
and  katabolic  activities  of  the  tissues  and  organs  involved. 

Albitsky3  has  shown  that  animals  subjected  to  repeated  fasting  lose 
body  weight  less  rapidly,  and  further  that  the  length  of  time  necessary 
to  secure  a definit  body  weight  loss  is  greater  than  during  the  initial 
fast.  A long  series  of  repeated  fasts  conducted  at  short  intervals  without 
bringing  the  animal  back  to  the  normal  condition  between  fasts  may  be 
accompanied  by  serious  results,  for  Richet  showed,  for  example,  that 
dogs  fasted  repeatedly  for  five  days  at  a time  lived  only  six  months, 
and  rabbits  fasted  at  six-day  intervals  lived  even  a shorter  time. 

Schulz12  presents  a theory  for  the  explanation  of  the  phenomena  of 
decreased  metabolism  during  interrupted  feeding  or  repeated  fasting. 
He  suggests  that  as  a result  of  the  removal  of  the  stimulation 
brought  about  by  ingested  food  the  activities  of  what  is  probably  the 
most  important  organ  involved  in  metabolism,  i.  e.,  the  liver,  are  impaired, 
and  consequently  the  protein  metabolism  is  led  into  abnormal  paths 
and  autointoxication  may  result.  This  phenomenon  of  autointoxica- 
tion must  be  capable  of  being  reduced  upon  the  re-entrance  of  the  stimu- 
lation of  food.  With  the  instigation  of  a new  fast  the  condition  of  increased 
metabolism  will  not  appear  and  as  a result  the  injury  resulting  from  the 
loss  of  the  stimulation  due  to  food  will  be  very  small,  or  will  be  entirely 
absent. 

It  is  clear  that  such  a theory  takes  no  account  of  any  metabolic  activi- 
ties other  than  those  centered  in  the  liver.  While  appreciating  to  the 
full  the  extremely  important  role  played  by  this  organ  in  the  metabolic 
activities  of  the  animal  body,  it  nevertheless  seems  highly  probable 
that  other  organs  are  involved  in  connection  with  the  decreased  protein 
katabolism  of  repeated  fasting. 

Schulz’s12  theory,  which  would  account  for  the  collapse  or  the  pre- 
mortal rise  as  due  to  a defective  liver  function,  is  not  substantiated  in 
the  case  of  our  dog,  for  it  is  evident  that  here  the  data  would  tend  to 
show  that  there  was  a certain  minimum  amount  of  protein  which  must 
be  present  in  the  body  in  order  that  life  shall  exist.  We  believe  this 
conclusion  to  be  warranted  from  the  fact  that  our  data  show  that  during 
each  fast  there  were  very  similar  amounts  of  nitrogen  excreted  notwith- 
standing one  fast  was  twice  as  long  as  the  other.  For  example,  during 


22 


fasting  studies. 


the  first  fast  of  fifteen  days  the  dog  lost  10.45  grams  of  nitrogen  per  kilo- 
gram of  body  weight,  whereas,  during  the  second  fast  of  thirty  dyes 
she  lost  11.60  grams  of  nitrogen  per  kilogram  of  body  weight.  In  other 
words,  at  the  end  of  each  fast  there  was  evidently  a similar  residual  quan- 
tity of  nitrogen-holding  substance  remaining  in  the  body,  the  nitrogen  of 
which  was  not  available  for  the  metabolic  uses  of  the  organism. 

Total  Nitrogen. — The  amount  of  nitrogen  excreted  in  the  urine  in  each 
fast  was  approximately  the  same,  i.  e.,  34.689  grams  in  the  first  fast  and 
39.430  grams  in  the  second.  The  greater  absolute  amount  of  nitro- 
gen excreted  during  the  second  fast  was  due,  partly,  to  the  increased 
amount  of  nitrogen  stored  during  the  intermediate  feeding  period  (80 
grams  of  muscular  tissue)  and  partly  to  the  fact  that  the  pre- 
mortal rise  of  the  first  fast  was  incomplete.  The  average  daily  excretion 
was  2.313  grams  of  nitrogen  for  the  first  and  1.3 13  grams  of  nitrogen  for 
the  second  fast. 

During  the  first  fast  the  total  nitrogen  excretion  increased  very  rapidly 
from  day  to  day,  denoting  a most  pronounced  acceleration  of  the  dis- 
integration of  muscular  tissue.  After  a drop  for  three  days,  a very 
marked  premortal  rise  occurred  on  the  last  day  (see  Table  I,  p.  30,  and 
figure  on  p.  12),  resulting  in  an  excretion  of  3.944  grams  of  nitrogen,  which 
was  1.472  grams  of  nitrogen  jnore  than  on  the  previous  day.  This  in- 
crease was  greater  than  the  average  daily  excretion  for  the  whole  period. 

The  rapid  loss  of  nitrogen  during  the  first  fast  might  be  ascribed  to  one  of 
two  things:  first,  a lack  of  fat  in  the  body,  or  second,  that  the  dog  was 
organically  unsound.  If  our  calculations  hold  good  (p.  20)  there  was 
more  fat  consumed  during  the  first  fast  than  during  the  second.  The 
increased  fat  deposit  (due  to  feeding)  amounted  to  but  50  grams  of  fat, 
and  was  also  accompanied  by  an  increase  in  muscular  tissue,  and  in 
body  weight.  It  is  evident  that  there  must  have  been  a good  store 
of  fat  in  the  body  before  the  first  fast.  This  presumption  was  substan- 
tiated by  the  feel  of  the  skin,  which  denoted  an  ample  subcutaneous 
fat  deposit.  Furthermore,  the  complete  recovery  of  the  dog  after  the 
first  fast,  and  the  fact  that  this  was  followed  by  a subsequent  fast  of 
twice  this  length  would  denote  an  organically  sound  animal.  The  post- 
mortem examination  substantiated  the  above  conclusion. 

These  are  general  deductions  but  sufficiently  strong  to  warrant  the 
premise  that  the  first  fast  was  normal  and  the  increased  excretion  of 
nitrogen  was  due  to  a rapid  normal  katabolism  of  the  muscular  tissues. 
This  is  further  substantiated  by  the  fact  that  more  fat  was  consumed 
during  the  first  fast  than  in  the  second,  notwithstanding  the  fact  that 
approximately  equal  amounts  of  nitrogen  were  excreted. 

The  rate  of  nitrogen  excretion  in  the  second  fast  was  in  marked  con- 
trast to  that  of  the  first  fast.  After  the  first  day  the  excretion  remained 


FASTING  STUDIES. 


23 


almost  constant  for  twenty-five  days  (an  average  of  1.238  grams)  when 
a gradual  premortal  rise  set  in,  the  excretion  for  the  last  sixteen  hours 
being  2.298  grams  of  nitrogen.  The  low  constant  excretion  during  the 
second  fast  was  that  observed  in  most  fasts,  and  accompanies  the  increased 
length  of  time  over  which  the  amount  of  available  nitrogen  was  metabo- 
lized, since  practically  the  same  total  amount  of  nitrogen  was  excreted  in 
each  fast. 

Urea. — The  nitrogen  excretion  as  urea  followed  the  total  nitrogen 
excretion  both  absolutely  and  relatively.  The  average  percentage  of 
urea  nitrogen  excreted  was  less  in  the  second  fast,  86.51  per  cent.,  or, 
excluding  the  three  days  upon  which  alkaline  fermentation  seemed  to 
have  occurred,  87.46  per  cent.  In  the  case  of  the  first  fast  the  percentage 
excretion  was  89.13  per  cent.  These  values  are  higher  than  the  average 
values  for  the  normal  diet.  The  fact  that  the  ratio  of  urea  nitrogen 
to  total  nitrogen  was  constant  has  been  discussed,  see  p.  13.  This 
constant  ratio  held  for  both  fasts. 

According  to  Folin’s56  theory,  the  relative  amount  of  urea  excreted 
varies  with  the  amount  of  total  nitrogen.  This  law  was  enunciated  with 
regard  to  normal  metabolism.  It  has  been  shown  in  our  laboratory23 
that  with  fasting  men  the  percentage  of  urea  nitrogen  decreases,  at 
least  for  a time.  Schondorf35  and  Underhill  and  Kleiner34  hold  this 
to  be  true  for  the  dog.  The  latter  investigators  report  a fourteen-day 
fast,  the  data  from  which  vary  considerably,  and  the  fluctuations  in  the 
percentage  of  urea  nitrogen  do  not  agree  with  those  of  the  total  nitrogen. 

In  fasting  man  the  decrease  in  the  percentage  of  urea  is  probably  due 
to  the  fatty  acids,60  which  by  combining  with  the  ammonia  prevent 
the  utilization  of  this  ammonia  in  the  formation  of  urea.  The  constant 
relative  urea  excretion  in  our  experiment  would  tend  to  show  that  fatty 
acids  or  acid  salts  were  probably  not  excreted  in  an  increased  amount 
during  the  fasting  period. 

There  is  a slight  increase  in  the  percentage  of  urea  nitrogen  excreted 
during  the  first  fast,  which  would  substantiate  Folin’s  theory  with  regard 
to  the  effect  of  an  increased  nitrogen  excretion.  However,  this  point 
is  more  strikingly  brought  out  in  the  case  of  the  intermediate  feeding 
period.  An  examination  of  Table  III,  p.  36,  will  show  that  the  percentage 
of  total  nitrogen  in  the  form  of  urea  increased  from  82.67  per  cent,  to 
86.51  per  cent.,  then  to  87.40  per  cent,  and  finally  to  88.74  Per  cent,  as 
the  diet  wTas  progressively  increased. 

It  appears,  therefore,  that  in  a fasting  dog  the  relative  urea  excretion 
follows  in  general  the  laws  of  relative  urea  excretion  which  obtain  for 
normal  feeding,  for,  with  an  increased  nitrogen  excretion,  as  in  the  first 
fast,  there  was  a slight  increase  in  the  relative  urea-nitrogen  excretion 
and  with  a low  and  constant  total  nitrogen  excretion  in  the  second  fast, 


24 


FASTING  STUDIES. 


there  was  a lower  and  more  constant  relative  urea  excretion.  Why  this 
should  hold  for  the  dog  and  not  for  man  is  not  clear.  It  may  be,  perhaps, 
that  the  dog,  being  a carnivorous  animal,  and  living  on  the  same  form 
of  food  in  each  case  (fresh  lean  meat,  and  muscular  tissue),  excretes  in 
each  instance  the  same  percentage  of  total  nitrogen  in  the  form  of  urea. 
Man,  on  the  other  hand,  being  unaccustomed  to  a diet  of  uncooked  lean 
meat,  finds  the  conditions  unusual  when  forced  to  exist  upon  his  own 
tissues  during  a fasting  test,  and  consequently  under  these  conditions 
a different  quota  of  the  total  nitrogen  output  is  eliminated  as  urea  than 
when  he  ingests  the  normal  mixed  diet. 

Ammonia. — The  ammonia-nitrogen  excretion  was  less  for  the  daily 
average  in  the  second  fast,  0.083  gram  or,  excluding  the  questionable 
days  already  mentioned,  0.068  gram  of  nitrogen  per  day,  as  against 
0.103  gram  of  nitrogen  in  the  first  fast.  Instead  of  increasing  from  day 
to  day,  as  in  the  fasts  of  men,  the  ammonia  remained  fairly  constant, 
following  the  total  nitrogen  excretion,  as  Folin56  has  pointed  out,  only  in 
that  when  the  total  nitrogen  excretion  was  low,  the  ammonia  was  abso- 
lutely lower,  but  relatively  higher.  A rise  in  the  ammonia  excretion 
at  the  end  corresponded  in  each  case  with  the  premortal  rise.  The  average 
ratio  of  ammonia  nitrogen  to  total  nitrogen  was  in  the  first  fast  4.59 
per  cent.,  and  in  the  second  fast  6.12  per  cent.,  or,  excluding  the  days 
of  alkaline  fermentation,  5.66  per  cent.,  which  shows  the  relatively  higher 
ammonia  excretion  during  the  second  fast.  The  facts  noted  here  with 
regard  to  the  ammonia  excretion  are  those  which  hold  in  normal  feeding. 

Creatinine. — The  marked  differences  in  the  total  nitrogen  excretions 
were  not  accompanied  by  similar  changes  in  the  creatinine-nitrogen  out- 
put. In  both  fasts  the  creatinine  nitrogen  fell  gradually,  the  average 
daily  excretion  for  each  period  being  almost  the  same,  that  for  the  first 
fast  being  0.025  gram  of  nitrogen  and  for  the  second  0.023  gram.  The 
total  amount  excreted  in  the  second  fast  was  nearly  twice  as  great  as 
that  of  the  first  fast,  the  output  of  creatinine  nitrogen,  therefore,  varying 
inversely  as  the  length  of  the  fast. 

Folin56  first  enunciated  the  law  that  the  amount  of  creatinine  excreted 
in  the  urine  by  a normal  individual  is  quite  independent  of  either  the  amount 
of  protein  in  the  food,  or  the  total  nitrogen  in  the  urine.  This  has  been 
confirmed  by  van  Hoogenhuyze  and  Verploegh,40  Klerker,61  Closson62 
and  Shaffer,63  whereas  Cathcart64  and  Paton65  fail  to  verify  this  theory. 
Folin  has  further  pointed  out  that  the  chief  factor  determining  the  amount 
of  creatinine  eliminated  appears  to  be  the  weight  of  the  individual,  and 
that  it  also  depends  upon  the  mass  of  active  protoplasmic  tissue.  Shaf- 
fer63 virtually  substantiates  this  theory.  The  creatinine  elimination 
in  fasting  man  has  been  observed  by  van  Hoogenhuyze  and  Verploegh, 
Benedict,41  Benedict  and  Diefendorf42  and  Cathcart,66  and  in  the  fasting 


FASTING  STUDIES. 


25 


dog  by  Underhill  and  Kleiner,34  and  Howe,  Mattill  and  Hawk,23  a gradual 
decrease  having  been  observed  in  each  case.  Underhill  and  Kleiner  state 
that  the  creatinine  excretion  is  variable.  Shaffer  lays  stress  upon  the 
creatinine  coefficient  (milligrams  per  kilogram  body  weight)  as  a constant 
for  individuals  of  an  equal  muscular  efficiency,  which  should  then  decrease 
for  a decreasing  muscular  efficiency. 

The  data  from  our  experiment  confirm,  in  the  main,  these  theories. 
With  a decreasing  body  weight  (loss  of  muscular  tissue)  and  muscular 
efficiency  there  is  a decrease  in  the  amount  of  creatinin  excreted  and  also 
in  the  creatinine  coefficient  (Table  V,  p.  38).  The  quantity  of  creatinine 
excreted,  per  day,  bears  a direct  relation  to  the  mass  of  active  muscular 
tissue  present  in  the  body.  The  creatinine  excreted  in  our  experiment 
does  not  bear  any  direct  relation  to  the  nitrogen  excretion,  for  we  have 
a similar  excretion  of  creatinine  in  the  two  fasts,  notwithstanding  the 
fact  that  the  rate  of  the  nitrogen  excretion  was  markedly  different  in  the 
two  cases  and  that  the  average  daily  excretion  of  total  nitrogen  was  nearly 
100  per  cent,  greater  in  the  first  than  in  the  second  fast. 

That  it  is  the  decrease  in  the  amount  of  active  protoplasm,  and  not 
merely  in  the  body  weight,  which  causes  a decrease  in  the  creatinine  excre- 
tion may  be  seen  from  an  examination  of  the  data  relative  to  the  creatinine 
coefficient.  If  the  decrease  were  coincident  with  the  decrease  in  weight 
the  creatinine  coefficient  would  remain  constant,  whereas  in  reality  it  de- 
creases more  slowly  than  the  body  weight.  This  dependence  upon  the 
mass  of  muscular  tissue  is  shown  in  the  intermediate  feeding  period.  As 
the  dog  gained  in  weight  and  stored  nitrogen  the  quantity  of  creatinine 
increased,  although  it  did  not  bear  any  direct  relation  to  the  amount 
of  nitrogen  excreted.  On  the  nineteenth  day,  or  at  the  time  34  per  cent, 
of  the  body  weight  lost  in  the  fast,  and  one-fourth  the  nitrogen  lost  had 
been  restored,  the  creatinine  coefficient  was  nearly  equal  to  that  before 
the  fast.  Furthermore,  on  the  twenty-fifth  day  or  at  the  time  the  animal 
had  regained  50  per  cent,  of  its  lost  nitrogen  and  body  weight,  the  creatinine 
coefficient  was  the  same  as  that  secured  before  the  fast  when  the  dog  was 
of  constant  body  weight  and  in  nitrogen  equilibrium.  If  current  ideas 
regarding  this  coefficient  are  correct  the  findings  indicate  that  the  animal 


possessed  equal  muscular  efficiency  under  the  two  conditions. 

The  above  may  be  substantiated  by  the  following  data : 

Total  amount  of  nitrogen  lost  during  first  fast 34.689  g. 

Creatinine  coefficient  before  fast  =12  mg. 

Nitrogen  stored  during  19  days  of  feeding  (creatinine  coefficient  n mg.) 

and  34  per  cent,  gain  in  body  weight 9 .015  g. 

Nitrogen  stored  during  25  days  of  feeding  (creatinine  coefficient  12  mg.) 

and  50  per  cent,  in  body  weight 17.157  g. 


We  thus  see  that  by  the  time  the  original  creatinine  coefficient  was 
restored,  i.  e.,  on  the  twenty-fifth  day  of  feeding,  the  mass  of  muscle  was 


26 


FASTING  STUDIES. 


only  50  per  cent,  of  that  present  before  the  fast.  If  we  are  to  hold  to  the 
idea  that  the  ingested  creatine  (in  the  meat)  and  the  amount  of  nitrogen 
excreted  have  no  effect  upon  the  creatinine  output,  then  in  order  that 
the  creatinine  coefficient  shall  be  significant,  we  must  suppose  a return 
to  the  original  condition  as  regards  muscular  efficiency  when  the  animal 
had  only  restored  one-half  of  its  nitrogen  and  body  weight.  The  dog 
certainly,  at  this  point  in  the  experiment,  exhibited  all  of  her  normal 
activity,  which  fact  tends  to  confirm  the  above  remarks  with  regard  to 
muscular  efficiency. 

Creatine. The  excretion  of  creatine  in  the  two  fasts  was  quite  similar, 

being  marked  by  a drop  in  the  creatine-nitrogen  excretion  at  the  beginning 
of  the  fast,  followed  by  a period  during  which  the  creatine  nitrogen  re- 
mained fairly  constant,  and  a little  less  than  the  creatinine  excretion. 
Toward  the  end  of  the  fast,  and  before  the  premortal  rise  there  was  a 
sudden  increase  in  the  amount  of  creatine  nitrogen  excreted,  being  greater 
than  the  creatinine  excretion.  This  increased  creatine  continued  to  the 
end.  This  marked  increase  of  the  creatine  excretion  over  the  amount 
of  creatinine  excreted  seems  to  be  an  indication  of  the  pronounced  metabolic 
irregularities  which  finally  result  in  the  inception  of  the  premortal  rise, 
and  occurs  from  two  to  three  days  before  the  drop  in  the  total  nitrogen 
excretion,  which  precedes  this  rise. 

The  amount  of  creatine  excreted  in  the  two  fasts  is  almost  equal,  corre-^ 
sponding  to  the  amount  of  total  nitrogen  excreted  during  the  periods 
in  which  creatine  was  determined.  Benedict,67  Mellanby,68  Shaffer,63 
Paton,65  Fowler  and  Hawk57  and  others  have  furnished  experimental 
evidence  in  support  of  the  theory  that  the  creatine  in  the  urine  arises  as 
a result  of  the  breakdown  of  the  muscular  tissues.  Paton  suggested 
that  the  discrepancy  between  the  amount  of  flesh  which  was  katabolized 
as  calculated  from  the  creatine  output  and  that  calculated  from  the  total 
nitrogen  may  be  due  to  the  resynthesis  of  a part  of  the  nitrogen  of  the 
broken-down  muscular  tissue,  the  creatine  being  excreted  at  the  time  of  j 
the  muscle  breakdown. 

Calculating  upon  the  basis  of  the  excretions  of  total  nitrogen  and  crea- 
tine nitrogen  we  have  derived  in  each  case  the  weight  of  the  mass  of  tissue 
katabolized,  assuming  the  accuracy  of  the  theory  that  urinary  creatine 
represents  disintegrated  muscular  tissue.  The  data  are  appended : 

Flesh  Lost  as  Calculated  from  the  Urinary  Total  Nitrogen  Data  and  from 
the  Creatine  Nitrogen  Data. 

First  Fast  (15  days). 

Nitrogen  lost— 34.689  grams. 

Equivalent  in  terms  of  flesh — (3.25%)  = 1069  grams 
Creatine  nitrogen  lost — 0.684  gram 
Equivalent  in  terms  of  flesh  (0.123%)  = 555  grams 


FASTING  STUDIES. 


27 

Second  Fast  (27  days). 

Nitrogen  lost — 33.524  grams 
Equivalent  in  terms  of  flesh  (3.25%)  = 1030  grams 
Creatine  nitrogen  lost — 0.689  gram 
Equivalent  in  terms  of  flesh — (0.123%)  = 560  grams 

The  amount  of  creatine  nitrogen  present  in  the  muscles  of  the  dog  at 
the  end  of  the  fast  was  0.042  per  cent.,70  showing  a very  marked  decrease 
(66  per  cent.)  in  the  amount  of  creatine  in  the  fasting  muscle  remaining 
in  the  body.  Dorner  has  reported  a somewhat  smaller  decrease  in  the  case 
of  rabbits’  muscle.  His  data  show  the  amount  of  creatine  in  this  tissue 
to  be  reduced  from  0.456  per  cent,  to  0.356  per  cent,  as  a result  of  fasting. 
This  pronounced  decrease  of  creatine  found  by  us  in  fasting  muscle  is 
a most  significant  fact  and  shows  clearly  that  in  fasting  we  cannot  with 
accuracy  consider  the  total  amount  of  excreted  creatine  as  resulting  from 
the  complete  and  permanent  disintegration  of  muscular  tissue.  How- 
ever, even  if  we  do  consider  all  of  the  excreted  creatine  as  having  this 
origin  we  have  shown  by  calculation  that  we  can  account  for  only  about 
one-half  of  the  total  nitrogen  on  this  basis.  The  discrepancy  between 
the  mass  of  muscular  tissue  lost,  calculated  on  the  two  bases,  i.  e.,  total 
nitrogen  and  creatine  nitrogen  output  becomes  all  the  more  striking 
when  we  appreciate  that  a large  part  of  the  creatine  excreted  during  the 
fasts  and  which  is  ordinarily  considered  as  representing  completely  dis- 
integrated muscular  tissue,  in  reality  most  certainly  does  not  represent 
this  but  rather  has  been  withdrawn  from  muscular  tissue  which  is  still 
functioning  as  living  tissue  within  the  body  of  the  animal.  Unfortu- 
nately no  determination  was  made  of  the  actual  mass  of  muscular  tissue 
remaining  in  the  body  after  fasting.  However,  inasmuch  as  we  have 
shown  in  this  laboratory70  that  the  total  nitrogen  content  of  fasting 
muscle  is  only  slightly  lower  than  that  of  well-nourished  muscle  it  is  evi- 
dent that  but  a small  fraction  of  the  total  nitrogen  excreted  by  the  urine 
arose  from  the  muscular  tissue  still  functioning  within  the  body,  whereas 
a comparatively  large  part  of  the  creatine  had  this  origin.  When  all 
these  facts  are  taken  into  consideration  it  is  apparent  that  over  50  per 
cent,  of  the  total  nitrogen  of  the  urine  had  a source  other  than  the  katabo- 
lism  of  muscular  tissue.  The  fact  that  fasting  muscle  may  have  its 
creatine  store  depleted  to  one-third  the  normal  while  retaining  its  nitro- 
gen content  but  slightly  lowered  indicates  rather  conclusively  that  the 
creatine  is  held  in  such  a combination  within  the  muscle  that  its  release 
is  not  necessarily  accompanied  by  the  disintegration  of  the  other  nitroge- 
nous muscle  constituents,  which  go  to  form  the  total  nitrogen  of  muscular 
tissue.68’  57  At  the  same  time  we  must  not  lose  sight  of  the  fact  that  the 
muscular  tissue  whose  nitrogen  store  is  seemingly  intact  at  the  end  of 
a fast  may  assume  this  condition  not  because  the  katabolic  processes 


28 


fasting  studies. 


have  not  been  sufficiently  profound  to  alter  its  inner  structure  but  rather 
because  of  certain  synthetic  reactions  which  have  followed  or  accompanied 
the  primary  disintegration  of  the  tissues.65  That  there  is  a direct  re1^ 
tion  between  the  amount  of  nitrogenous  material  katabolized  and  the 
creatine  excreted  is  brought  out  in  our  results.  For  example,  with  prac- 
tically the  same  amount  of  nitrogen  excreted  under  the  same  conditions 
i.  e.  two  fasts  continuing  to  the  premortal  rise,  and  with  two  equal 
but  decidedly  different  rates  of  nitrogen  excretion,  practically  the  same 

amount  of  creatine  was  excreted.  . 

No  direct  evidence  has  been  obtained  which  would  show  the  relation 
between  creatine  and  creatinine.  The  creatine  appears  to  be  derived  either 
from  disintegrating  muscular  tissue  or  to  be  removed  in  s°“e  “r 
from  such  tissues  which  are  still  functioning  within  the  body.  The 
creatine  excretion  was  low  during  the  first  part  of  each  fast,  increasing 
suddenly  a few  days  before  the  drop  in  the  total  nitrogen  excretion  wh  ch 
preceded  the  premortal  rise.  From  this  time  to  the  end  of  the  fast  the 
daily  output  of  creatine  nitrogen  exceeded  that  of  the  creatinine  nitrogen. 
Dorner  69  in  the  case  of  a rabbit  which  died  after  nine  days  of  fasting, 
found  the  creatine  excretion  of  the  second  day  to  exceed  that  of  creatimne. 

Summary. 

A fox  terrier  bitch  about  one  year  old  and  weighing  3-41  kilograms 
was  brought  into  nitrogen  equilibrium  and  was  subjected  to  two  fasts. 
On  the  fifteenth  day  of  the  first  fast  the  premortal  rise  m nitrogen ^out- 
put was  noted  and  was  accompanied  by  other  signs  indicating  that  death 
would  result  in  a few  hours.  She  was  then  carefully  fed  and  dunng 
the  feeding  period  of  forty-seven  days  regained  her  former  weight  and 
was  again  brought  into  nitrogen  equilibrium,  after  which  she  was  fasted 
Tsecond  time  for  a period  of  thirty  days.  The  animal  was  in  fully  as 
good  physical  condition  at  the  beginning  of  the  second  as  she  wa 

at  the  commencement  of  the  first  fast.  .. 

The  water  ingestion  was  uniform  (250  «.)  throughout  the  feeding 
and  fasting  periods.  The  loss  in  body  weight  was  nearly  equal  in  each 
fast  being  45.75  per  cent,  for  the  first  and  46.04  per  cent,  for  the 
second  fast.  However,  on  the  fifteenth  day  of  the  second  fast’  t'  e'’ 
after  a period  equaling  in  length  the  entire  first  fast,  the  animal  had 
lost  but  25.42  per  cent,  of  her  body  weight. 

From  the  data  obtained  we  have  shown  that:  . 

1 With  a practically  equal  total  nitrogen  excretion,  the  rate  of  t 
excretion  was  widely  different  in  the  two  fasts,  being  high  and  rapidy 
increasing  during  the  first  fast  of  fifteen  days,  and  low  and  fairly  con- 
stant during  the  second  fast  of  thirty  days.  A premortal  rise  occurred 

at  the  end  of  each  fast.  . « 

2.  The  absolute  amount  of  urea  nitrogen  excreted  was  in  direct  re  a- 


FASTING  STUDIES. 


29 


tion  to  the  total  nitrogen  excretion.  The  relative  urea-nitrogen  ex- 
cretion remained  practically  constant  throughout  the  fasts,  but  increased 
with  an  increased  total  nitrogen  excretion  during  the  intermediate 
feeding  period. 

3.  The  ammonia-nitrogen  excretion  remained  fairly  constant,  varying 
with  the  total  nitrogen  excretion  in  that  when  this  was  low  the  ammonia- 
nitrogen  was  absolutely  lower  but  relatively  higher. 

4.  The  creatinine-nitrogen  excretion  decreased  very  uniformly  and 
gradually  as  the  fasts  progressed,  and  increased  uniformly  and  gradually 
during  the  intermediate  feeding  period.  The  total  output  of  creatinine 
nitrogen  varied  inversely  as  the  length  of  the  fast.  On  the  nineteenth 
day  of  the  feeding  period,  or  at  the  time  thirty-four  per  cent,  of  the  body 
weight  lost  in  the  first  fast,  and  one-fourth  the  nitrogen  lost,  had  been 
restored,  the  creatinine  coefficient  was  nearly  equal  to  that  before  the 
fast.  Furthermore,  on  the  twenty-fifth  day  or  at  the  time  the  animal 
had  regained  only  fifty  per  cent,  of  its  lost  nitrogen  and  body  weight, 
the  creatinine  coefficient  was  the  same  as  that  secured  before  the  fast  when 
the  dog  was  of  constant  body  weight  and  in  nitrogen  equilibrium. 

5.  The  total  amount  of  creatine  nitrogen  excreted  was  practically  the 
>ame  during  each  fast.  The  average  daily  amount  of  creatine  nitrogen, 
fowever,  was  nearly  twice  as  great  during  the  first  fast  as  during  the 
second  fast. 

6.  The  allantoin  and  purine  nitrogen  excretions  decreased  as  a result 
)f  the  fast  and  were  practically  equal  for  each  fast. 

7.  The  undetermined  nitrogen  decreased  as  a result  of  fasting.  The 
iverage  daily  amount  of  undetermined  nitrogen  in  the  second  was 
me-half  that  in  the  first  fast. 

8.  A consideration  of  the  summation  of  the  nitrogen  balances  shows 
hat  there  is  a minimum  amount  of  nitrogen  which  must  be  present  in 
he  body  in  order  that  life  shall  exist. 

9.  The  excretion  of  urinary  creatine  increased  suddenly  a few  days 
>efore  the  drop  in  the  total  nitrogen  excretion  which  precedes  the  pre- 
tiortal  rise.  From  this  time  to  the  end  of  the  fast  the  daily  output  of 
reatine  nitrogen  exceeded  that  of  the  creatinine  nitrogen. 

10.  Assuming  the  accuracy  of  the  theory  that  the  urinary  creatine 
epresents  disintegrated  muscular  tissue  and  calculating  accordingly, 

• discrepancy  exists  between  the  calculated  mass  of  muscular  tissue 
3st,  when  considered  from  the  standpoint  of  total  nitrogen  and  creatine 
itrogen  respectively.  When  all  the  facts  in  this  connection  are  taken 
ito  consideration  it  is  apparent  that  over  fifty  per  cent,  of  the  total 
itrogen  had  a source  other  than  the  muscular  tissue. 

11.  The  creatine  content  of  muscle  showed  a marked  decrease  (over 
ixty  per  cent.)  as  a result  of  fasting,  while  the  nitrogen  content  of  similar 


Tabus  I. — General  Data. 


FASTING  STUDIES. 


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00 

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in 

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O'  >0  M O to  CO  O'  O O'  o vo 

CM  N o ^ to  O to  IO  -J-  N CM 


CMCMCMCMCMCMCMCM 


rt-  O'  o O N M 00  r-.  o N to  IO 
co  CO'OiO'O'OOtOOOMJOtO 
VO  'tO'MOO  lOtO^  NN-t>0 


mmCMMCMCMCMCMCMCMCMCMCO 


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*o  ‘o  ‘o  'o  *3  ‘3  *3  *3  ‘3  *3  '3  '3  *3  '3 

cj  rtctJctJctJc5ctJc3o3rtrtc3a3ctJ 


in 

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VO  co  00  M IO  VO  CO  VO  VO  VO  O'  00  00  CM 

CM  CMi-iCMCMMCMCMCMCMCM(NCMCO 


rj-  LO  M VO 
O ON  OV  CO 


00  O Ov  M CM  WO)  IO 

VO  VO  ^ to  CM  o 00 


cococococmcmcmcmcmcmcmcmcmcmm 


cm  CO  ^ IO  VO  00  O'  O 


N to  Th  IO 


944  3-544 


FASTING  STUDIES. 


31 


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to 

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13  13 


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a a-c  -c  -a  -o  -g  3 

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to  m m 

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m O 00  N Ov  o 00  00  O >0  VO  lO  O 
d*  to  co  tO  VO  vo  VO  Ov  O 00  CO  vo  d" 
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ro  Ov  to  vo  d*  m <0 

« N N M « N « 


10  10  >0  vj- 
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Table  I ( continued ). 


3 2 


FASTING  STUDIES. 


a 

& "o 


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a^a 

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io  io  »o  to 

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r^rt-ioio»o0»o00,jO00K-itocs000 
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CN  CN 


o CS 
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CN  01 


73  be  bo 


rj-  IO  CN  O 

co  co  as  o 


ON  o 

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CN  CN  CN  COCOCOCOCOCOCOCOCOCOCOCOCOCO 


"*■  CO 

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O'  O ih  cn  co  rt-  to  vo  oo  O'  O ►« 

CN  (OCOtOCOCOcOcOcOtOO't't 


212  1005  acid  1.209  1.058  0.052  0.030  0.014 


FASTING  STUDIES. 


33 


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00  N VO  00 
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o o 
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t}-  m 

to  co 

o o 
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ON  Cl 
CO  VO 

o o 
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m 

10  10 

o o 

d o 


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O O co  O'  Cl  O 


M M M O M M 


O »o 


H 00  00  00 

C-~  Cl  NO 
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*0  '3 

o3  ca 


3 IS 
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ca  ca 


8 8 S 8 8 8 8 8 8 


CO  »0 

•O  CO  c)-  CO  10  10  CO 

O 


OOOOBOO 


CO  vo  co 

^■•tTt-iOlO't't'tlOIOtN 

0000000000 
0000000000 


•O  NO  rj- 
O H VO 

Cl  Cl  d 


Cl  00 
Cl  -3- 

1-1  ci 


co  Th 
10  II 
ci  ci 


1-iOONCOCCt^l-ITt- 
CO  1-1  O CO  CO  ON  CO  Cl 
CICICICICIWCICI 


>0  »0  O NO 

11  M vo  rj- 
Cl  Cl  Cl  Cl 


Cl  N N N N 


VO  M 
Cl  M 

CO  CO  co  M to  N 


>0  1^1-1 
O O ON 


CICICICICICICICICICICICICICICICNCICICICIW 


CO'CJ-COVO  t>»  00  ON  o m Cl  corj-covo  t^OO  On  O m Cl  CO  co  NO  t>.00  On  O 

mmmmmmmmmmcicicicici<icicici(i<0 


1 66  cc.  of  urine,  diluted  to  264  cc. 


34 

Day. 

I 

2 

3 

4 

5 

6 

7 

8 

;! 

3 

4 

5 

6 

7 

8 

9 

io 

ii 

12 

13 

14 

15 

2-3 

4 

5 

6 

7 

8 

9 

io 

ii 

12 

13 

14 

15-16 

17-18 

19 

20 

21-22 


FASTING  STUDIES. 


Table  II. — Percentage  Nitrogen  Distribution. 


Urea  N.  Ammonia  N.  Creatinine  N.  Creatine  N.  Purine  N.  Allantoin  N.  Undeter  N. 

Preliminary  Feeding  Period. 


86.96 

384 

1.88 

2-95 

0.70 

88.10 

4.18 

1.68 

3-59 

0.09 

i-45 

86.65 

4.64 

i-52 

1.25 

0 . 1 1 

5.82 

86.82 

4-57 

1.47 

2 .01 

0.58 

0.16 

4-38 

84.85 

5.67 

1. 41 

0.51 

0.24 

0.90 

6.42 

85.15 

6.92 

i-45 

2-49 

0-54 

0-34 

3-io 

89-93 

4.24 

1 .08 

3.28 

0.24 

1.25 

85.84 

7.29 

i-45 

First 

2 .62 

Fast. 

2.79 

8751 

4.48 

2.28 

1.40 

0.23 

0.49 

3.60 

86.84 

6.24 

i-95 

1. 41 

3-56 

89-54 

4.44 

1.63 

1.63 

2-75 

89.78 

5.87 

1 .60 

1 .02 

0.27 

0.18 

1 .29 

86.36 

6.07 

1.23 

1 .61 

0.32 

0.21 

4.08 

91 . 12 

3-99 

113 

1 .02 

2.74 

88.26 

5-ii 

M3 

1 .60 

0.04 

0.04 

3.8i 

90.97 

3.64 

0.98 

2.05 

0.23 

2 .12 

90.00 

3-67 

0-93 

2.23 

0.22 

0.07 

2.88 

89.84 

3-78 

0.86 

2.70 

0-43 

0.14 

2.23 

88.92 

4-39 

0.76 

3. 10 

0.04 

0.08 

2.70 

89.19 

4.14 

0-59 

2 .80 

0.16 

O.16 

2 .96 

89.56 

4.45 

0.48 

2-79 

0.28 

0.28 

2.14 

89.86 

4.06 

0.46  1.77 

Feeding  Periods. 
Preliminary. 

0.30 

3.60 

91 .01 

3-59 

0-34 

1-52 

4.01 

82.45 

7 .00 

1.50 

2 <~9 

0.42 

0.48 

5-15 

74-53 

1105 

1.63  2.56 

Normal  Diet. 

0.46 

0-93 

8.84 

85-55 

5.82 

0.96 

2.65 

0.44 

0.07 

4-50 

81.30 

11.46 

0.92 

2-34 

0-33 

0.05 

3-59 

85-37 

6-93 

0-93 

0.87 

0-35 

0.06 

5 48 

86.58 

6-33 

113 

2-57 

0.38 

0.06 

2-95 

89.27 

4-95 

1. 14 

3 05 

0.38 

0.06 

1 14 

87.14 

4-74 

1. 14 

3-54 

o.33 

3” 

86.99 

5.23 

1 .04 

316 

0.31 

327 

87.31 

5.26 

0.94 

2.47 

0.32 

3-68 

87.96 

512? 

0.78 

1 .84 

0.31 

384 

87.06 

5 08) 

2.31 

0.40 

0-59 

3-37 

85.62 

6.61 

1 . 10 

2.91 

0.27 

0-43 

3 04 

88.27 

5-24 

1 . 12 

2 . 11 

0.36 

0.64 

2 .26 

86.21 

6.90 

1.38  2.86 

50%  Increase  in  Diet. 

0-34 

0-59 

1.82 

86.21 

6.90 

1 .00 

3-04 

0.27 

0.46 

2.12 

87.23 

5.19 

0.94 

3-44 

0.23 

0.68 

2-43 

FASTING  STUDIES. 


35 


Table  II  ( continued ). 


Day. 

Urea  N. 

Ammonia  N. 

Creatinine  N.  Creatine  N. 
50%  Increase  in  Diet. 

Purine  N. 

Allantoin  N.  Undeter. : 

23-24 

87-59 

5 • 11 

1 .01 

3-67 

O.24 

0.69 

1 .61 

25-26 

87-73 

5-32 

1. 17 

4-23 

O.27 

O.44 

0.77 

27 

88.25 

4.14 

1.32  4.52 

100%  Increase  in  Diet. 

0-34 

O.23 

1 .21 

28 

88.25 

4-13 

0-95 

3.26 

O.24 

O.16 

2.99 

29-30 

89.21 

4-38 

0.86 

3-13 

0-37 

2.05 

31-32 

87.56 

4.46 

o-99 

3-69 

O.27 

3-02 

33-34 

87.62 

4-73 

0.88 

2 .81 

O.17 

3.78 

35-36 

86.51 

4-97 

1 .00 

3-72 

0.28 

0.21 

3.05 

37-38 

88.02 

4.17 

1 .00 

3-39 

0-37 

0.05 

2.97 

39-40 

87.83 

4.67 

o-99 

3-33 

0-39 

0.05 

2 .69 

41-42 

87.82 

4 05 

1 .01 

2.94 

O.36 

0.05 

3-7i 

43-44 

87.87 

4.08 

1.03  3-47 

Normal  Diet. 

0-37 

0.05 

3 05 

45-46 

87.19 

4-63 

1.67 

3.46 

0-33 

0.20 

2 .72 

47 

86.44 

4-56 

1.60  1.89 

Second  Fast. 

0-33 

0.21 

4-97 

1 

87.05 

4-25 

2.96 

2.68 

0.28 

2.78 

2 

86.54 

4.84 

2 .67 

2-59 

O.25 

3 09 

■ 3 

87-51 

4-30 

2 .48 

1 .16 

0-33 

O.4I 

3- 80 

| 4 

88.10 

3-25 

2 .82 

2-33 

0-33 

O.42 

2-74 

5 

86.81 

4-95 

2 .48 

2.56 

O.32 

O.4O 

2 .48 

6 

89-53 

3-46 

2.31 

1.77 

O.27 

o-34 

2.31 

7 

87.32 

5 05 

2-39 

1 . 60  ... 

O.36 

0.44 

2 .84 

8 

88.38 

5-12 

1 .90 

i-75 

O.29 

0.36 

2 . 19 

9 

N 

00 

6.07 

2.05 

1 -31 

0-33 

0.41 

2.38 

10 

88 . 44 

6.28 

2.18 

1 .01 

0-34 

0.42 

i-34 

11 

88.60 

6.03 

2 .07 

1 .21 

0-34 

o-43 

1 .29 

12 

88.06 

5-85 

2 .02 

i-43 

0.30 

o-37 

i-95 

13 

87.84 

6.26 

1 .84 

1 .03 

0.30 

2-73 

14 

86.97 

7 .02 

2.03 

0.68 

0.34 

2 .96 

15 

90.88 

6.96 

1 .90 

1 .32 

0-33 

16 

88.02 

4.91 

1.49 

1 -71 

0.30 

17 

78.54 

14.92 

1 .61 

1 .61 

0.36 

2-95 

18 

85.92 

7.12 

1.76 

2 . 10 

0-34 

2-77 

19 

Si-95 

10.30 

1.50 

2 .62 

0-37 

0.15 

3 07 

20 

88.07 

4-93 

i-43 

2.86 

O.40 

0. 16 

2.15 

21 

86.49 

5-49 

1 -31 

2.87 

O.41 

0.16 

3-2 

22 

76.56 

6.32 

1 . 16 

3-16 

O.42 

1 • l7 

12.307 

23 

82  .05 

10.57 

0.99 

2-51 

O.46 

0.23 

3-19 

24 

88.08 

6.74 

0.98 

1.97 

O.49 

0.25 

1 .48 

25 

87-59 

6.46 

1.05 

2.36 

O.52 

0.26 

1-75 

26 

86.23 

5-33 

1 .06 

3-64 

0-53 

0.27 

2-93 

27 

88.16 

4-35 

0-94 

3-54 

O.41 

0.20 

2.41 

28 

87.49 

5-46 

29 

87.41 

7-33 

30 

88.59 

7.92 

36 


FASTING  STUDIES. 


Table  III. — Summary  of  Nitrogen  Excretion. 


Total 

Urea  Ammonia 

Crea-  1 

Creatine 

Purine  Allantoin  Unde- 

Period  (diet). 

N. 

N.  N. 

tinine  N. 

N. 

N. 

N.  ter.  N. 

Period  Averages — Grams  per  Day. 

Preliminary  . 

. .2 .768 

2.405  0.143 

O.041 

O.056 

0.012 

0.008  0.109 

First  Fast  . . 

. . .2.313 

2.065  0.103 

O.025 

O.O46 

0.005 

0.005  0.067 

Prelim.  Feed. 

.. .1.356 

1.162  0.105 

0.012 

O.O29 

0.070 

Normal 

.. .I.833 

1.587  0.112 

0.020 

O.054 

0.076 

50% 

. . .2.689 

2.351  0.142 

0.028 

O.  102 

- 0.008 

O . 008  O . 045 

100% 

. . .4071 

3.576  0.178 

O.O4O 

0.134 

O.124 

Normal 

2.132  0.113 

O.O4O 

0.072  _ 

0.085. 

Second  Fast  . 

. • .1.314 

1.141  0.083 

0.023 

0.026 

0.005 

O.OO4  O.032 

Period  Averages — Per  < 

cent. 

Preliminary  . 

. . ... 

86.79  5-17 

I.49 

2 .01 

0-45 

0.31  4-03 

First  Fast. . . 

89  13  4-59 

I. 14 

1.94 

0.22 

0.26  2.89 

Prelim.  Feed. 

82.67  7.21 

I . II 

2.36 

0-45 

0.71  6.00 

Normal 

86.51  6.13 

1.05 

2.51 

0-35 

0.28  3.25 

50% 

87-40  5-33 

1 .09 

3.78 

O.27 

0.50  1.63 

100% 

88.74  4.40 

0.97 

3.30 

O.4O 

0.15  3 03 

Normal 

86.81  4.59 

I.63 

2.68 

0-33 

0.20  3.56 

Second  Fast  . 

86.51*  6.12f 

1.85 

2.05 

O.38 

0.31  2.58 

Total  Weight  of  Nitrogen  Excreted  in  Urine  (Grams). 

First  Fast. . . 

. .34-689 

30.972  1.550 

0-373 

0.684 

Second  Fast . 

. -39-430 

34.224  2.483 

0.6ll 

0.689 

Table  IV. — Nitrogen  Balances. 

N in  hair. 

Total  N 

N in  urine. 

feces  and  cage 

output. 

N in  food. 

Day. 

Grams. 

wash.  Gram. 

Grams. 

Grams. 

N balance. 

Preliminary  Period. 

1 

2.707 

0.235 

2.942 

2.732 

0.210 

2 

2.202 

0.235 

2-437 

2.732 

+ O . 295 

3 

2.63O 

0.235 

2.865 

2.732 

— 0.133 

4 

2.580 

0.235 

2.815 

2.732 

O.083 

5 

2-555 

0.235 

2.790 

2.732 

— O.O58 

6 

2.964 

0.235 

3-199 

2.732 

— O.467 

7 

3-683 

0.235 

3.918 

2.732 

I . l86 

8 

2.825 

0.235 

3.060 

2.732 

— O.328 

First  Fast. 

2.634 

0.064 

2.762 

2 . 762 

3 

I.489 

0.064 

1-553 

— 1-553 

4 

I .960 

0.064 

2 .024 

— 2 .024 

5 

2.250 

0.064 

2.314 

— 2.314 

6 

1.862 

0.064 

1 .926 

— 1 .926 

7 

2.558 

0.064 

2.622 

— 2 .622 

8 

2.308 

0.064 

2.372 

— 2.372 

9 

2.637 

0.064 

2 .701 

— 2.701 

io 

2 .780 

0.064 

2.844 

— 2.844 

* See  discussion,  p.  17. 

-j-  See  discussion,  pp.  17-18. 


FASTING  STUDIES. 


37 


Table  IV  (< continued 


N in  hair, 

Total  N 

N in  urine. 

feces  and  cage 

output. 

N in  food. 

Day. 

Grams. 

wash.  Gram. 

Grams. 

Grams. 

N balance 

First  Fast. 

II 

2.777 

0.064 

2 .841 

— 2 .841 

12 

2.483 

0.064 

2-547 

— 2-547 

13 

2-535 

0.064 

2-599 

— 2.599 

14 

2.472 

0.064 

2.536 

— 2.536 

15 

3-944 

0.064 

4.008 

— 4 . 008 

Feeding  Periods. 

Preliminary. 

I 

2.893 

0. 161 

3-054 

0.198 

— 2.856 

3 

1 .670 

0. 161 

1.992 

I .848 

— O.144 

4 

0.860 

0. 161 

1 .021 

2.239 

+ I. 218 

Normal  Diet. 

5 

1-356 

0. 161 

I-5I7 

2.465 

+ O . 948 

6 

1 .840 

0. 161 

2 .001 

2.732 

+ O.731 

7 

1.716 

0. 161 

1.877 

2.732 

+ 0.855 

8 

1-595 

0.161 

i-756 

to 

G> 

to 

+ 0.976 

9 

i-576 

0 . 161 

1-737 

2.732 

+ O.995 

10 

1-835 

0. 161 

1.996 

2.732 

+0.736 

11 

1.929 

0. 161 

2 .090 

2.732 

4-  0.642 

12 

1.900 

0. 161 

2 .061 

2.732 

4-  0.671 

13 

1.952 

0. 161 

2.113 

2.732 

4-  0.619 

14 

I-5I5 

0. 161 

1 .676 

2.732 

4-  1.056 

15-16 

4.368 

0.322 

4.690 

5-464 

+ 0.774 

17-18 

3-889 

0.322 

4.211 

5.464 

+ 1-253 

19 

2.030 

0 . 161 

2 . 191 

2.732 

+ 0.541 

50%  Increase  in  Diet. 

20 

2-594 

0.247 

2.841 

4.104 

+ 1.263 

21-22 

5-545 

0.494 

6.039 

8.208 

4-  2 . 169 

23-24 

5-535 

0.494 

6 .029 

8.208 

+ 2.179 

25-26 

5-183 

0.494 

5-677 

8.208 

+ 2.531 

27 

2.655 

0.247 

2 .902 

4.IO4 

4-  1 .202 

100%  Increase  in  Diet. 

28 

3-682 

0.256 

3-938 

5-464 

+ 1.526 

29-30 

7-858 

0.512 

8.370 

IO.928 

+ 2.558 

31-32  . 

7.286 

0.512 

7.798 

IO.928 

+ 3-i3o 

33-34 

8-577 

0.512 

9.089 

IO.928 

+ 1.839 

35-36 

7 .606 

0.512 

8.118 

IO.928 

4-  2 .810 

37-38 

8.56O 

0.512 

9.072 

IO.928 

+ 1.856 

39-40 

fO 

00 

cs 

00 

0.512 

8-795 

IO.928 

+ 2.133 

41-42 

8.762 

0.512 

9.274 

10.928 

+ 1-654 

43-44 

8.592 

0.512 

9.104 

IO.928 

4-  1.824 

Normal  Diet. 

45-46 

4.920 

0.634 

5-554 

5-464 

— 0.090 

47 

2.435 

0.317 

2.752 

2.732 

4-  0.020 

Day. 

I 

2 

3 

4 

5 

6 

7 

8 

9 

io 

ii 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

26 

27 

28 

29 

30 

iy. 

6 

7 

8 

i 

2 

3 

;S 

6 

7 


FASTING  STUDIES. 


Table  IV  ( continued ). 


N in  hair, 

Total  N 

- 

N in  urine. 
Grams. 

feces  and  cage 
wash.  Gram. 

output. 

Grams. 

N in  food. 
Grams. 

N balance. 

Second  Fast. 

I .081 

0.054 

i -135 

— 1 135 

i .197 

0.054 

1 .251 

— 1*251 

1.209 

0.054 

1.263 

— 1263 

1 .202 

0.054 

1.256 

— I .256 

1 .251 

0.054 

1305 

— 1.305 

1 .471 

0.054 

1.525 

— 1.525 

1.128 

0.054 

1 . 182 

— I . 182 

1.368 

0.054 

1 .422 

— I .422 

1 .218 

0.054 

1 .272 

— I.272 

1. 194 
1.158 

0.054 

0.054 

1 .248 

1 .212 

— I .248 

I .212 

1-332 

0.054 

1.386 

— I .386 

1 -357 

0.054 

1 .411 

I .41  * 

1 . 182 

0.054 

1.236 

I .236 

1.207 

0.054 

1 .261 

I .261 

1-344 

0.054 

1*398 

— I .398 

1 .119 

0.054 

1.273 

— I.273 

1. 193 

1 -335 

0.054 

0.054 

1.247 

1.389 

—I.247 
— 1.389 

1.257 

1 .221 

0.045 

0.054 

1 .311 

1*275 

— i -311 

— 1.275 

1 .203 

0.054 

1.257 

— 1*257 

1 .315 

0.054 

1.369 

— 1369 

1 .216 

0.054 

1 .270 

— 1 .270 

1. 145 
1.126 

0.054 

0.054 

1. 199 

1 .180 

— 1. 199 

— 1 . 180 

1 -495 

0.054 

i*549 

— 1*549 

i«5*9 

2 .089 

0.054 

0.054 

i*573 

2*143 

1 * 573 

— 2.143 

2.298 

0.054 

2.352 

— 2.352 

Table  V. — Body  Weight  and  Creatinine  Coefficient. 


Body 

weight. 

Kgs. 

Gross  gain 
or  loss. 
Kgs. 

Daily  gain 
or  loss. 

Kgs. 

Per  cent, 
gross  gain 
or  loss. 

Per  cent, 
daily  gain 
or  loss. 

Creatinine 

coefficient. 

3-42 

3.40 

3-4* 

Preliminary  Period. 

N N 

OOO 

O06 

First  Fast. 

3.26 

3*9 

3**3 

— 0.15 

0.22 

0.28 

— 0.15 

— 0.07 

— 0.06 

—4.40 

6-45 

8.21 

—4.40 

2.15 

1.88 

O . 009 

0.009 

O .009 

2-95 

O.46 

— 0.18 

13-49 

5-75 

O.OII 

2.91 

2.86 

— 0.50 

— 0-55 

— 0.04 

— 0.05 

14.66 

16.13 

1-35 

I.72 

0 .008 

0.010 

FASTING  STUDIES.  39 


Table  V (continued). 


Body 

weight. 

Gross  gain 
or  loss. 

Daily  gain 
or  loss. 

Per  cent, 
gross  gain 

Per  cent, 
daily  gain 

Creatinine 

Day. 

Kgs. 

Kgs. 

Kg. 

or  loss. 

or  loss. 

coefficient. 

8 

ft 

2.77 

— O.64 

First  Fast. 

— 0.09 

18.77 

3-15 

0.009 

9 

IO\ 

2.60 

— O.81 

— 0.17 

23-75 

6.14 

0.010 

j 

ii 

2.49 

— O.92 

— 0. 11 

26.98 

4-23 

0.009 

12 

2.31 

— I .IO 

— 0.18 

32.26 

7-23 

0.008 

13 

2.22 

— I.I9 

— 0.09 

34-6o 

3-90 

O.OO7 

14 

2.05 

— 1.36 

— 0.17 

39.88 

7.66 

0.005 

15 

I.85 

— 1.56 

— 0.20 

45-75 

9-75 

0.008 

i 

i*95 

+ 0.10 

Feeding  Periods. 

Preliminary. 

+ 0.10  +6.41 

+ 5-40 

0.005 

2 

2.25 

+ 0.40 

+ 0.30 

25-63 

15- ,38 

0.006 

3 

2-35 

+ 0.50 

+ 0.10 

32.04 

4.44 

0.006 

4 

2 .24 

+ 0.39 

— 0. 11 

24.99 

— 4.68 

0.006 

5 

2 .20 

+ 0.35 

Normal  Diet. 

— 0.04 

22.43 

— 1.78 

0.006 

6 

2 . 12 

+ 0.27 

— 0.08 

17.30 

— 3-64 

O.OOS 

7 

2 . 19 

+ 0.34 

+ 0.07 

21.80 

+ 3-30 

0.008 

8 

2 .24 

+ 0.39 

+ 0.05 

24.99 

2.28 

0.008 

9 

2.25 

+ 0.40 

+ 0.01 

25.63 

0-45 

0.008 

IO 

2 .26 

+ 0.41 

+ 0.01 

26.27 

0-44 

0.009 

ji 

2 .27 

+ 0.42 

+ 0.01 

26.91 

0-44 

O.OO9 

12 

2 .29 

+ 0.44 

+ 0.02 

28.20 

0.88 

0.008 

*3 

2.28 

+ 0.43 

— 0.01 

27.56 

— 0.44 

0.008 

14 

2.31 

+ 0.46 

+ 0.03 

29.48 

+ 1. 31 

0.008 

15 

2-34 

+ 0.49 

+ 0.03 

31.40 

1.29 

0.010 

16 

2.36 

+ 0.51 

+ 0.02 

32.68 

0.85 

0.010 

17 

2.36 

+ 0.51 

0.00 

32.68 

0.00 

0.009 

1 8 

2.36 

+ 0.51 

0.00 

32.68 

0.00 

0.009 

19 

2.38 

+ 0.53 

+ 0.02 

33-96 

0.85 

O.OII 

20 

2 .42 

+ 0.57 

50%  Increase  in  Diet. 

+ 0.04  +36.53 

+ 1.68 

O.OII 

21 

2.49 

+ 0.64 

+ 0.07 

41 .01 

2.89 

O.OII 

22 

2.50 

+ 0.65 

+ 0.01 

41.65 

0.40 

0.010 

23 

2*57 

+ 0.72 

+ 0.07 

46.14 

2.80 

O.OII 

24 

2 .61 

+ 0.76 

+ 0.04 

48.70 

i-55 

O.OII 

25 

2.63 

+ 0.78 

+ 0.02 

49.98 

0-77 

0.012 

26 

2 .67 

+ 0 . 82 

+ 0.04 

52.55 

1-52 

O.OII 

27 

2-75 

+ 0.90 

+ 0.08 

57-67 

3.00 

0.013 

28 

2.84 

+ 0.99 

100%  Increase  in  Diet. 

+ 0.09  63.44 

3-27 

0.013 

29 

2.85 

+ 1 .00 

+ 0.01 

64.08 

0-35 

0.012 

30 

2.92 

+ 1 .07 

+ 0.07 

68.57 

2-45 

0.012 

31 

3-00* 

+ J 

+ 0.08 

73-70 

2.74 

0.012 

32 

3 00 

-4  J JK 

00 

73-70 

0.00 

0.012 

33 

34 

35 

36 

37 

38 

39 

40 

4i 

42 

43 

44 

45 

46 

47 

I 

2 

3 

4 

5 

6 

7 

8 

9 

io 

ii 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

22 

23 

24 

25 

26 

27 

28 

29 


FASTING  STUDIES. 


Table  V ( continued ). 


Body 

weight. 

Kgs. 

Gross  gain 
or  loss. 
Kgs. 

Daily  gain 
or  loss. 

Kg. 

Per  cent, 
gross  gain 
or  loss. 

Per  cent, 
daily  gain 
or  loss. 

100%  Increase  in 

Diet. 

3 09 

+ 1.24 

+ O.09 

79.46 

3-00 

3.10 

+ 1.25 

+ 0.01 

80.10 

O.32 

3.20 

+ i-35 

+ 0.10 

86.50 

3.22 

3-24 

+ i-39 

+ 0.04 

89.08 

I.25 

3-32 

+ i-47 

+ 0.08 

94.20 

2-47 

3-35 

+ 1.50 

+ 0.03 

96.12 

O.90 

3 40 

+ i-55 

+ 0.05 

99-33 

I.49 

3 -46 

+ 1 .61 

+ 0.06 

103.17 

1.76 

3-50 

+ 1.65 

+ 0.04 

105.74 

1 . 16 

3*52 

+ 1.67 

+ 0.02 

107.02 

0-57 

3-56 

+ 1. 71 

+ O.O4 

109.58 

1. 14 

3-59 

+ 1-74 

+ 0.03 

Normal  Diet. 

hi  .50 

0.84 

3-56 

+ 1. 71 

— 0.03 

109.58 

— 0.83 

3-54 

+ 1.69 

— 0.02 

108.30 

— 0.56 

3-54 

+ 1.69 

0.00 

108.30 

0.00 

Second  Fast. 

3-42 

— 0.12 

— 0.12 

— 3-39 

— 3-39 

3-32 

— 0.22 

— 0. 10 

6.21 

2 .92 

3.26 

— 0.28 

— 0.06 

7.91 

1. 81 

3-n 

— 0.43 

— 0.15 

12.15 

4.60 

3 07 

— 0.47 

— 0.04 

13-28 

1.28 

3 05 

— 0.49 

— 0.02 

13.84 

0.65 

2-95 

— 0-59 

— 0. 10 

16.66 

3.28 

2.89 

— 0.65 

— 0.06 

18.36 

2.03 

2.86 

— 0.68 

— 0.03 

19.21 

1 .04 

2.80 

— 0.74 

— 0.06 

20.90 

2 . 10 

2.77 

— 0.77 

— 0.03 

21-75 

1.07 

2.72 

— 0.82 

— 0.05 

23.16 

1 .80 

2.68 

— 0.86 

— 0.04 

24.29 

1.47 

2.64 

— 0.90 

— 0.04 

25-42 

1.49 

2.58 

— 0.96 

— 0.06 

27 . 12 

2 .27 

2.51 

— 1.03 

— 0.07 

29.09 

2.71 

2.49 

— 1.05 

— 0.02 

29.66 

0-79 

2-45 

— 1.09 

— 0.04 

30.79 

1.60 

2.40 

— 1. 14 

— 0.05 

32.20 

2 .04 

2-37 

— 1. 17 

— 0.03 

33-05 

1-25 

2.36 

— 1. 18 

— 0.01 

33-33 

0.42 

2.31 

— 1.23 

— 0.05 

34-74 

2 . 12 

2.21 

— 1-33 

— 0. 10 

37-57 

4-33 

2.18 

— 1.36 

— 0.03 

38.42 

i-35 

2.15 

— 1-39 

— 0.03 

39-26 

i-37 

2 . 11 

— i-43 

— 0.04 

40.39 

1.86 

2.05 

— 1.49 

— 0.06 

42.09 

2.84 

1.97 

— i-57 

— 0.08 

44-35 

3-90 

1. 91 

— 1.63 

— 0.06 

46.04 

Creatinine 

coefficient. 

0.013 
0.012 
0.012 
0.012 
0.013 
0.013 
0.013 
0.012 
0.013 
0.013 
0.013 
O .012 

O.OII 

0.012 

O.OII 

0.009 

0.009 

O.OO9 

0.010 

0.010 

0.009 
0.009 
0.009 
0.009 
0.008 
0.010 
o .009 
0.009 
0.009 
O.OOS 
0.006 
O .008 
0.008 
0.008 
0.007 
0.006 
0.006 
0.005 
0.005 
0.006 
0.006 


FASTING  STUDIES.  4 1 


Table  VI. — Nitrogen  in  Diet,  Feces,  Hair  and  Cage  Washings. 

Feeding  periods. 


Preliminary 

period. 

11  days. 

First 

fast. 

15  days. 

Pre-  5056 

liminary.  Normal,  increase. 

4 days.  15  days.  8 days. 

100$ 

increase. 
17  days. 

Normal. 

3 days. 

Second 

fast. 

30  days. 

Food  (per  day). 

Meat 2.533 

3.618*  2.533  3-799 

5.066 

2-533 

Crackers 0.1977 

2.930*  0.1977  0.303 

0-395 

O.1977 

Lard 0 . 0008 

0.003*  0.0008  0.0012 

0.002 

0.0008 

Bone  ash.  . . . 0.0003 

0 . 003*  0 . 0003  0 . 0005 

0.0005 

0.0003 

Total  (grams)  2 . 732 

6.554*  2.732  4.104 

5.464 

2.732 

HaO 250  cc. 

250  CC. 

250  cc.  250  cc.  250  cc. 

250  CC. 

250  CC. 

250  CC. 

Feces. 

Grams 41 .89 

3-5 

76.6  61.0 

92 .0 

20.0 

9.6 

Wt.  of  N 1.691 

O.309 

2.143  1.596 

3-540 

0-739 

0.776 

% N 4.037 

8.874 

2.798  2.616 

3-839 

3-695 

8.100 

Gms.N  per  day  0.154 

0.021 

0.113  0.199 

0.208 

O.269 

0.026 

Hair. 

Grams 5.0 

130 

6.0 

Wt.  of  N 0.575 

1-555 

0.666 

% N 11.50 

11.961 

11 . 100 

Gms.N  per  day  0.052 

0.025 

0.022 

Cage  washings. 

Wt.  of  N 0.326 

0.268 

1 . 084  (47  days) 

0.189 

Gms.N  per  day  0.029 

O.OI78  O.O23 

0.006 

Total  Nitrogen  Excreted. 

Grams 2.592 

. . 

. . 

Gram  per  day  0.235 

0.064 

0.161  0.247 

0.256 

O.317 

0.054 

muscle  was  but  slightly  lowered.  This  pronounced  decrease  of  creatine 
found  by  us  in  fasting  muscle  is  a most  significant  fact  and  shows  clearly 
that  in  fasting  we  can  not,  with  accuracy,  consider  the  total  amount  of 
excreted  creatine  as  resulting  from  the  complete  and  permanent  disin- 
tegration of  muscular  tissue.  It  appears  that  the  creatine  of  the  urine 
is  derived  either  from  disintegrating  muscular  tissue  or  is  removed,  in 
some  manner  from  such  tissues  which  are  still  functioning  within  the  body. 

12.  As  a result  of  our  experiments  we  have  shown  that  in  repeated 
fasting  there  is  a slower  and  less  profound  tissue  disintegration  during 
the  second  fast,  indicating  a greater  resistance  of  the  body,  acquired  as 
a result  of  the  initial  fast.  This  increased  resistance,  noted  in  our  ex- 
periments, following  fasting  may  indicate  that  the  “repeated  fast,”  if 
properly  regulated,  may  possess  important  therapeutic  properties.  The 
gi  eater  length  of  the  second  fast  could  not  have  been  due  to  increased 
fat  stores,  for  the  fat  present  in  the  body  of  the  animal  at  the  beginning 
of  the  second  fast  was,  according  to  our  calculations,  only  fifty  grams 
more  than  at  the  beginning  of  the  first  fast. 

* Total  weight  of  nitrogen  fed  during  the  four  days. 


42 


FASTING  STUDIES. 


References. 

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Pashutin,  Pathological  Physiology , 1902.  Quoted  by  Pashutin.1  3.  Albitsky.  4. 
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gold, p.  419.  10.  Schulz  and  Stiibel,  p.  431.  11.  Schulz  and  Hempel,  p.  439.  12. 

Schulz,  p.  462;)  Arch.  ges.  Physiol .,  114,  1906.  13.  Voit,  Z.  fur  Biol.,  2,  307 

(1866).  14.  Seeland,  Biol.  Centr.,  7,  145  (1887).  15.  Richet,  Compt.  rend.  soc. 

biol.,  61,  546  (1906).  Quoted  by  Pashutin.  16.  Rucher.  17.  Smith.  18.  Ranke. 
19.  Pettenkofer  and  Voit.  20.  Oppenheim.  21.  Sadoven.  22.  Richet.  23.  Howe, 
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(1899).  28.  Grandis,  Arch.  ital.  biol.,  12,  237  (1889).  29.  Krawkaw,  Wratsch,  1891. 

30.  L’abb6  and  Vitry,  Compt.  rend  soc.  biol.,  62,  699  (1907).  31.  Luciani  and  Bufalini, 

Arch.  sci.  med.,  5,  338  (1882).  32.  Folin,  Z.  physiol.  Chem.,  41,  233  (1904).  33.  Oster- 

berg  and  Wolf,  Biochem.  Z.,  5,  304  (1907).  34.  Underhill  and  Kleiner,  J.  Biol.  Chem., 

4,  165  (1908).  35.  Schondorf,  Arch.  ges.  Physiol.,  117,257(1907).  36.  Leffmann, 

Z.  physiol.  Chem.,  57,  476  (1908).  37.  Weber,  Arch.  exp.  Path.  Pharm.,  58,  93  (1907). 

38.  Dorner,  Z.  physiol.  Chem.,  52,  93  (1907).  39.  Bohtlingk,  Arch.  sci.  biol.  St. 

Petersburg,  8,  483  (1903).  40.  Van  Hoogenhuyze  and  Verploegh,  Z.  physiol.  Chem., 

46,  415  (1905).  41.  Benedict,  Carnegie  Institution  of  Washington,  Publication  No. 

77,  386  (1907).  42.  Benedict  and  Diefendorf,  Am.  J.  Physiol.,  18,  362  (1907).  43. 

Cathcart,  Biochem.  Z.,  6,  109  (1907).  44.  Gies,  Am.  J.  Physiol.,  5,  235  (1901).  45. 

Hawk,  University  of  Pennsylvania  Medical  Bulletin,  Dec.,  1905.  46.  Gies,  Am. 

Physiol.,  14,  403  (1905).  47.  Hawk  and  Grindley,  Proc.  Am.  Soc.  Biol.  Chem.,  1908. 

9.  Gill  and  Grindley,  J.  A.  C.  S.,  31,  695  (1909).  48.  Marcuse,  Arch.  Physiol., 

59,  232  (1896).  49.  Benedict  and  Gephart,  J.  A.  C.  S.,  30,  1760  (1908).  50. 

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Chem.,  37,  161  (1902).  53.  Benedict  and  Meyers,  Am.  J.  Physiol.,  18,  397  (1907). 

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Nutrition,  1909,  46.  56.  Folin,  Am.  J.  Physiol.,  13,  66  (1905).  57.  Fowler  and 
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(1907).  62.  Closson,  Am.  J.  Physiol.,  16,  252  (1906).  63.  Shaffer,  Am.  J.  Physiol ., 
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Festschrift,  p.  15. 

1 These  references  were  obtained  from  the  English  translation  of  Pashutin’s 
book,  prepared  under  the  direction  of  Francis  G.  Benedict  of  the  Carnegie  Institution. 


VITA 

The  author  graduated  from  the  University  of  Illinois  in  1906  with 
the  degree  of  Bachelor  of  Science  in  Chemistry.  He  received  a scholar- 
ship in  chemistry,  in  the  University  of  Illinois  for  the  year  1906  to  1907, 
and  obtained  the  degree  of  Master  of  Arts  in  1907,  from  that  institution, 
with  a thesis  in  physical  chemistry.  During  the  following  year  he  was 
assistant  chemist  in  the  Laboratory  of  Physiological  Chemistry  of  the 
University  of  Illinois  and  did  graduate  work  in  physiological  chemistry. 
As  assistant  in  physiological  chemistry  in  the  University  of  Illinois  he 
pursued  * graduate  courses  in  physiological  chemistry,  under  Professor 
Philip  B.  Hawk,  and  in  physiology  and  histology. 

He  is  a member  of  Phi  Lambda  Upsilon,  Sigma  Xi,  the  Gamma 
Alpha  Graduate  Scientific  Fraternity,  the  American  Chemical  Society, 
the  American  Association  for  the  Advancement  of  Science,  the  American 
Society  of  Animal  Nutrition,  the  Illinois  Academy  of  Science,  the  Ameri- 
can Society  of  Biological  Chemists,  and  the  American  Health  League. 

PUBLICATIONS 

1.  “The  Electrolytic  Corrosion  of  Brasses”  (with  Azariah  T.  Lincoln 
and  David  Klein):  Journal  of  Physical  Chemistry , 11,  501  (1907). 

2.  “Comparative  Tests  of  Spiro’s  and  Folin’s  Methods  for  the  Deter- 
mination of  Ammonia  and  Urea”  (with  P.  B.  Hawk) : Journal  of  Biolog - 
ical  Chemistry , 5,  477  (1909). 

3.  “On  the  Preservation  of  Feces”  (with  T.  A.  Rutherford  and  P.  B. 
Hawk):  Proceedings  of  the  American  Society  of  Biological  Chemists , 

1909,  xlix. 

4.  “A  Study  in  Repeated  Fasting”  (with  P.  B.  Hawk) : Proceedings 
of  the  American  Society  of  Biological  Chemists , July,  1910. 

5.  “Fasting  Studies  on  Men  and  Dogs”  (with  H.  A.  Mattill  and  P.  B. 
Hawk) : Proceedings  of  the  American  Society  of  Biological  Chemists , 

July.  I91O. 

The  author  wishes  to  express  his  sincere  thanks  to  Professor  Philip 
B.  Hawk,  under  whose  direction  this  investigation  was  conducted,  for 
the  kindly  counsel  and  unerring  advice,  which  were  stimulating  factors 
during  the  progress  of  this  research  and  through  the  author’s  graduate 
work  in  general. 


